First off, this isn't a debate thread. GaaS is a relatively new term, so I don't think there's any right or wrong answer for defining it. I just want to know what you personally define GaaS as, and what, if any GaaS games you consider to be good or bad. 

GaaS stands for Games as a Service. That's in contrast to Games as a Product. With Games as a Product you pay once for a complete product, and then maybe pay a few additional times for accessory products (DLC). The basic idea behind GaaS is to get your playerbase to constantly fork over money for the game, kinda like paying a utility. Because of this, I would say, any game that expects regular influxes of cash from its playerbase, post initial purchase, to be GaaS. Technically, Animal Crossing is a GaaS game, because it expects its playerbase to pay for Nintendo Online post initial purchase. The line between GaaS and GaaP can get pretty blurry though. If a company puts out four sets of DLC for their game a year is that now GaaS? Or did they just make four accessory products for their game?

I think a good answer to this question is to say that GaaS is a spectrum. At one end of the Spectrum we have games that only expect you to pay a small fee to play online, but are mostly a one time purchase. In the middle of the spectrum we have fighting games like Smash Ultimate, or DBFighterZ. These games put out somewhat frequent character DLCs, and expect people to pay for online. At the far end of the spectrum we have games like Destiny, Fortnite, Anthem, Gears 5 and Genshin Impact. These games have almost constant drops of micro-dlc, that are overly expensive. They weaponize FOMO and/or use other psychological hooks to get their playerbase to constantly play. Games on this far end of the spectrum are a lot like collectible card games, in that they expect their players to dedicate all their time and money to them. Games on the opposite end of the spectrum are like one time board game purchases. 

Personally, I think the closer a game is to the GaaP end of the spectrum, the better a game it is. Games on this end of the spectrum are a much better bang for your buck. Games on the far end of the GaaS spectrum wind up costing their players far too much time and money in the long run. 

Finally, I'd like to point out that not all GaaS games have MTX. One of the first games to come out on the far end of the GaaS Spectrum was World of Warcraft. With WoW you just had to pay a monthly fee after initial purchase. 

As for what GaaS games are good or bad? I think Animal Crossing, Smash, and even WoW are examples of GaaS done right. I think Destiny, Fortnite, and MK11 are far too predatory for their own good. 

P.S. I'm predicting that Halo Infinite, and TLoU Multiplayer Edition will both be games that lean heavily into the GaaS end of the spectrum. Not only that, but they will both be bad games. 

Considering your spectrum I would not consider games that have planed multiple drops in a yeear as GaaS as that is schedule to finish. The thing with destiny and the like is they are planed to be for ever going. With no planed end the player is forever traped in an endles cycle to pay for the content of the month. On the first scenario you spend prbably double the asking price in small chunks, but the second is infinite if you get sucked in.

To answer your question then GaaS would be consider a game with no planed end where they can suck money from you by hooking you in.
Who done it good or bad? I would say that to do it good or bad is determined by the paywall. Games like Path of exile I say do it right cuz they add content thats meaninfull, not in a schedule weekly/monthly or whatever just to have something to keep you dosed up. they also dont charge for the updates and all their DLC is pure cosmetic. players achive everything by actual gameplay.
Now WoW I would belive is the worst ofender here. A monthly sub for a game in this date and age is just agregious. Destiny is another bad one as they make you buy the update as it comes out while at the same time having abusive microtransactions and time limited event where you are baasicly forced to pay if you are hooked.

So basicly like you said a bad GaaS is determined by if the dev abused the FOMO t extract cash from players and just makes it predtory. But a Good one not only has to not be predatory but also have meaninfull content update, even if not frequent.

Not faith in halo as 343i have a bad record and who knows about TloU. Buut I dont really have faith in any GaaS. Theres just to few gems out the piles of crap for me to trust the entire category of games.

Both are good I guess.  I hope neither cease to exist anytime soon, I don't often spend many time in the same game so game as product are what I like the most. They are usually more polished and better designed as well.

But this comparison is ultimately pointless if we are comparing single player campaign, as Game as a Service rely much more in multiplayer side of the business without a very clear goal and set of missions to beat 

Hence I will make my assertions based only on games with heavy online features, multiplayer focus and regular updates with missions and events:

Games as a Service are much better from a consumer standpoint 

- When the game is a product you buy it and if you dont like you lose your money and that's about it

- When the game is a service you pay just as long you want to enjoy the game or you just dont pay anything at all if you don't want to

To start, most Game as a Service are mostly ""free"" to play

Service games are more likely to keep getting updates and so on. And if if you become tired of Game as Services due to its "infinite" nature you can just download another other game for a very small price or even without paying anything. For people who are low on cash it means you don't need to expect another paycheck before getting something new 

If a game is intended to be multiplayer heavy and is sold as a 60 USD finished product and then flops I guess you can say goodbye to your money (right ARMS?). That's exactly the reason I haven't bought Crash Team Reacing yet. It's a game that I like mostly from multiplayer and I don't want to pay full price in a game that I will need to spend my day to find a single online match. The lack of new tracks and characters annoys me as well, I'd rather get this game for free to increase the userbase and then fill it with MTX  I don't see the problem with MTX you can just don't pay for it if you don't want it. But a fucking multiplayer game that is a true desert that nobody plays? That's annoys me much much more than any MTX

And you are talking about Smash. What exactly is good about smash? Paying 30 USD to get what 2 new characters a year? Yikes

A new Smash fighter costs $5.99 each. Considering that many games ask $10 for a simple skin, I'd say that's a good deal, and fair pricing. 

What about admit both are shit?

A new skin is often as little as changing some textures. A new character for a fighting game requires an entirely new 3D model, a whole new moveset, sound effects, particle effects, balancing issues, etc. 

Fair. Still you have to pay 60 USD for smash, while games that offers overpriced cosmetic changes are often free. Of course if people are dumb to pay 10 USD for a cosmetic change that's their right, but I don't mind a game filled with paid cosmetic changes to the sole fact that I don't feel even slightly inclined to spend money on skins and other clothes. 

The type of MTX that I find annoying are the ones that comes from games like Candy Crush Saga where the game is designed to make you spend money to get some "boost" to finish the level. Some levels are borderline impossible to finish without spending some cash buying items 

I've spend around 40 USD on a mobile game that I only played 20-30 minutes a day when I was commuting. When I realized that I just uninstalled the game, this is the type of GaaS that I don't really support 

First of all, the GAAS trend is too common for my tastes. It especially annoys me when it's applied to pre-existing IPs. But there are some that have done it relatively well.

Animal Crossing: New Horizons - Now I never wanted this approach for Animal Crossing. However, let's examine what it has given us....
-Items
-Events
-Emotes/make-up
-More features (diving, artwork, etc)
All for free.
Star Wars: Battlefront II: This started out as a disaster. Thankfully, Dice really turned things around. By time I got Battlefront in early 2020, there was a lot to love.
While I appreciate that Super Smash Bros. Ultimate has given us some free new features (stage builder), it's not making my list. The fighter packs and season passes are overpriced. I still buy them because I want every stage and fighter.
Rocket League: I'd put off buying it for a long time. Once it was finally free, I jumped on board.

Yeah games I would consider to be Gaas are some of the ones you mentioned, like Destiny and Anthem, also Fallout 76, upcoming games like (I imagine), Outriders. Also I consider Paradox games to be good examples of singleplayer games as a service, with Europa Universalis 4 exemplifying the case. 

Fortnite and Apex and CoD:Warzone and such games I think are better described as "free to play" since I think that carries with it the understanding there will be microtransactions, "battlepasses", boxes and other such items. 

So in that light i'd define a Gaas a bit more strongly than you do. A paid-for game which releases significant gameplay content that affects the base game behind a paywall. 

Some games do this very badly (like the original Destiny) which seemed to release as a kind of £50 prologue. Some games also make players who don't pay up for the next big title update feel like second-class players, with DLC map areas obnoxiously greyed out to devalue the original content. But some games do it very very well. EU4 is one of them. Their DLC introduces significant changes to the way the game plays, but not buying it still leaves the original mechanics in the game and leaves no trace of its absence.

This means that games mentioned here like..

Animal Crossing (no paid expansions)

Gears 5 (cosmetics only)

Smash Ultimate (cosmetics only) 

... wouldn't properly qualify as games as a service in my book. 

To me, GaaS is simply a game that continuously adds new content and experiences in the game. There is really no end to the game, you can continue playing and continue having new content. That's where the service part comes in. It doesn't have to be paid DLC, a lot of the service/seasonal content in GaaS titles are free. In many, you don't have to spend a dime to experience new content, you just might have to wait longer than those that do.

The definition of good or bad GaaS varies from person to person because we all have different tastes. You have railed against Gears 5 plenty of times about so called predatory skin pricing, etc etc. I would consider Gears a GaaS title done right. It's constantly updated with new stuff free of charge. Forza Horizon 4 is another prime example of GaaS done right. The map and content changes literally with the seasons throughout the year. It's spring, you have different terrain and events than you had during winter. Again this is all free, you don't have to spend a penny. Other games don't do it very well. Imho there is a clear difference between a developer looking to provide meaningful content for long periods of time, and those just looking to entice gamers to grind away for scraps of content. Avengers is a recent example of a GaaS done wrong. They seemed more worried about future DLC and monetization than worrying about in game content at launch. Anthem was another victim of this. In contrast, Ubi did a great job with the first Division. The second one, they went a bit overboard with monetization. They also did a good job with Siege.

Last gen most of my play time was gobbled up by games I'd consider to be GaaS. Evolve, Battleborn, Destiny, Dead by Daylight. Even GOTG Titanfall added elements of GaaS with seasonal ranked play and daily challenges plus burn cards, but that game had zero monetization outside of map packs. Nowadays you see plenty of single player games adding GaaS elements with rotating challenges, leaderboards, and seasonal content. It's been proven dramatically that when done correctly, it works.

It definitely rubs some people the wrong way. Many just can't get over the idea of spending so much time or money on one game. For example, Dead by Daylight I've probably spent close to $250 at least on content in the game. That seems crazy to some, but I've played the game for thousands of hours so factually, that's incredible value. I'm adding it up right now, here's what I actually spent:

Base game: $32
Michael Myers: $9
Leatherface: $5
Fredward Krueger: $9
Head case (charity skins): $4
SAW chapter: $9
Clown: $9
Spirit: $9
More charity DLC: $5
Legion: $9
Ghost Face: $5
Stranger Things: $13
Deathslinger: $9
Silent Hill: $8

I've also spent $146 on the DbD in game currency, some to buy skins, some to buy season passes, some to buy other new characters. Grand total of $281, worth every penny.