Beautiful thread!

Xenoblade 2 will be my first game of the series/saga. It definitely deserves a try... looks beautiful and creative.

Boy you're missing out. I would recommend you to play the previous games before, they're all very accessible nowadays besides Xenosaga. Although Xenoblade 2 might be very different to the previous 2 anyway.

Xenogears and Xenosaga were HOT ASS MESSES. This man is way too ambitious for the budgets that he's given. I love Xenosaga to death, but just like Xenogears, they're both scream "missing something"; in these cases: "MISSING A WHOLE LOT OF STORYLINE".

A few of them would've been Pachinko and Dancing All Night games. 

Unfortunately, I'll have to start with Xenoblade 2 anyway. If Nintendo remaster the previous Xenoblades, or at least release them on the eShop, I'll definitely get them.

Interesting thread. I would also recommend to place the links to the videos so people on a mobile device could see them.

There is also Soma Bringer, but that is Japan only. Takahashi was the producer and designer, Saga -- the writer. 

Updated with links, and with a blurb about Xenogears Perfect Works under the Xenogears section, with a link to the album of the entire book.
Kunihiko Tanaka's name has been added in as well to Xenoblade Episode 2 - I forgot to mention him, as the loss of his and Saga's character art style hurt the game a lot IMO - he was involved with Xenoblade Chronicles, although I am unsure as to what capacity other than he was likely working on creatures rather than characters this time around - it seems to me that Nopon and some of the characters match his art style - but clearly Xenoblade Chronicles X is much more in his style.
Norihiro Takami - was the head artist of Xenoblade Chronicles, other notable credits include Final Fantasy 8 FMV art director and Legend of Zelda Breath of the Wild Associate Director (which probably means he was managing tasks and timelines for one of the teams departments, I am not sure Nintendo EAD's dev structure).

On Chrono Trigger - I am aware of Takahashi's work on that series, as well as a dozen other games (FF4 and 5, and 7, Secret of Mana, Front Mission, etc...) but I am unsure of what portions of those games are his. Soraya Saga's also worked on other games. Truth be told, the first game they worked on at the same time was Final Fantasy 5, Soraya Saga designed the map for that game, and Tetsuya Takahashi designed the graphics for the map - so that was most likely their original collaboration. Final Fantasy 6 seemed a better intro considering their work on it was noteworthy and impressive, and helped elevate the game.
Interesting to note, the concept for Xenogears used to be the concept for Final Fantasy 7 - you can still see a lot of Soraya Saga and Tetsuya Takahashi's influence on that game. The link between Sephiroth and Cloud, as well as the psychological issues, are more than likely adaptations from Saga and Takahashi's original concept. Deus, in Xenogears, began as Lavos, and Gears began as Magitek Armour. If you're playing XCX and flying around in Skells, you are, in a way, playing the latest version of FF6's Magitek Armour.

Soma Bringer I am aware of as well. In all honesty, I have never played this game, nor do I know very much about it. Hopefully one day we see it released over here.

^ that is actually a shame.

Should go play the first Xenoblade (on wii/wiiu) game, is a good one.

You won't spoil yourself in anything but themes and plot structure when playing newer games over older ones.

Many of the plot mechanics of Xenoblade Chronicles and Xenoblade Chronicles X are from (mostly) Xenogears and (a bit from) Xenosaga.

A few off the top of my head (and yes SPOILERS, if you haven't played these games):

*BEGINNING OF SPOILERS*

1. Main character does a task which introduces the first town and characters. Home town suffering an attack by giant robots, main character finds power, and main character's love interest is killed (Xenogears and Xenoblade)
2. Humans turn out to exist to be "food" for God (Xenogears and Xenoblade).
3. The "God" isn't a real god, but rather a creation of a past human civilization (Xenogears and Xenoblade).
4. The spirit of God is from a another universe (in Xenogears a higher dimension, and in Xenoblade and Xenosaga, a prior universe).
5. The master race is transformed into terrible creatures for the purpose of God (Xenogears Wels, and Xenopblade Telethia).
6. A sacred figure resides in the main female secondary character (Eve/Hawwa in Elly, Mary Magdalene in KosMos, and Mayneth in Xenoblade).
7. A sacred figure resides in the main character (Abel/Contact of God in Fei, and Zanza in Shulk).
8. Cyclical timeline (Xenosaga, universe gets destroyed and reformed, same thing happened to a lesser extent in Xenoblade).
9. Higher dimensional beings entered the universe at the beginning of time (Xenogears, and Xenoblade, XCX, presumably Xenosaga - even though it wasn't delved into with Xenosaga and Xenoblade, they were more about a past universe).
10. Destruction of the alpha civilization (Solaris, Shvat, and Alcamoth)
11. Two civilizations of greater power who are enemies, with the most powerful (good) civilization not really acting in any huge capacity against the "evil" civilization - Shevat and Alcamoth against Solaris and Mechons).
12. The evil civilization isn't really evil (Solaris and Mechonis)
13. The main villain(s) turns out to not be truly evil (Ramsus, Krelian, Grahf, Albedo, Egill)

Similar themes too, Giant robots controlled by humans (all games, Xenogears has the most extensive approach: Humans riding traditional control mechs, humans controlling Gears directly with their brains, and a merger of human and Gear into a sort of a hybrid living machine).

Xenogears is definitely the most robust story, Xenosaga not as robust of a plot, but there's definitely more stuff that happens in that trilogy than perhaps all the others combined. Xenogears and Xenoblade are the only two that are complete stories, while Xenosaga and XCX are left with an open end. Xenogears delves into the distant past A LOT more than the others, while Xenosaga goes more into the past overall - but instead of hundreds to thousands of years ago, it is mostly in the last 50 years (Shion, Junior, Momo, and Mizrahi's lives). Both Xenogears and Xenoblade have a lot of "What's this ancient thing?" type stuff in them - Xenogears is a bit more interesting in this regard because you uncover well preserved civilizations with a lot of development, while the Giant civ and Agniratha aren't very well developed or as impressive.

*END OF SPOILERS*

Xenogears might not work for everyone - because:
1. It's a very plot heavy story, there's a lot of knowledge you have to retain, and many players lose track of stuff and can't make sense of it all on their first playthough; some will claim that the story seems like it is all over the place - but it's not really, it's a very direct plot. A single replay of the game typically is enough for players who didn't get it the first time to get it.
2. The graphical style isn't for everyone. It's not a full 3D game, the characters are sprite based, and placed into a polygonal 3D setting. Although, if you're a fan of DS style games, you'll probably be fine with these graphics, since they were common on that platform's RPGs.

To sort of categorize them:

1. Xenogears is closest in style to a traditional RPG like Final Fantasy 4 to 9 but, it has a lot more plot. Towns are huge and segmented there are multiple cities that are the size of Midgar in Xenogears; and one of them is bigger. It has a lot of depth, it starts out like a seemingly normal RPG and then goes crazy about 10-15 hours in, and becomes a multi-threaded plotline with plots surrounding villain characters, past existing characters, and other main characters; as the main climax is the climax of all these major plot threads. It'll give you the most bang for your buck in hours to plot delivered. There is not much filler in this game, even the two portions of the game that feel like filler (the caverns and the sewers) actually end up having fairly big significance. The second disk changes format, and this rubs most people the wrong way the first time through (due to the stylistic change); but the second time through it's generally people's favourite part of the game - or one of their favourite parts as there's some really cool stuff in this game that have special significance to various people.

2. Xenosaga is more like the Final Fantasy X and 13 style, although far more cinematic and focused on story segments. It is slow moving, and not paced consistently - like the beginning has very little in the way of battles, and then toward the end there is a three hour portion of wandering through a virtual world and killing enemies. This can be offputting to people their first time, if they aren't expecting this. Xenosaga 2 and 3 are more consistently paced, but clearly the budgets on these games were lower, and Takahashi didn't have the artistic freedom on these two that he did on the first game. They're not bad games, they're still very good, and IMO it is not because of the lack of Takahashi's freedom, but in spite of it - he had set up a very good foundation for the franchise, and it finished.

3. Xenoblade is a little like Xenosaga with much less focus on cutscenes and more focus on wandering around and exploring. The story has more of a step by step feel with only minimal numbers of twists and turning points. In style, it feels closest to Xenosaga 2 IMO (and surprisingly), but it doesn't have the same sort of confined feeling of XS2. Also, the battle system is different: in Xenosaga the game was three ATBs, each attached to a single character, and each had a list of commands they could use each time the ATB expired - Xenoblade has 8 ATBs all attached to one character, and each coincides with a single move. It is a simple single threaded plot which splits a little toward the end with Egill.

4. XCX is much more open world - the world is vast, and you can go everywhere. There is a large hub city (New LA). Each chapter has a set of sub-stories which can be completed, and when certain key sub stories are complete, then the player can move to the next chapter - moving to the next chapter can significantly alter the state of the city of New LA and the political system.

It's misleading when people say this game has less story than Xenoblade, as there's actually a lot more. The difference is that Xenoblade's story is that the story deals almost completely with one character - Shulk - while the story of Xenoblade Chronicles X deals mostly with the establishment of New LA as a civilization. In addition, unlike Xenoblade which largely focuses on a single plot, XCX has a bunch of smaller plots that help develop the main story (it's not like Xenogears where it is a multithreaded plot line where stuff is carried through until the end, as many of these plots get resolved within the chapter). In the end, there's a lot more story in XCX than Xenoblade. Where it doesn't have as much is the main character's plot; but that certainly doesn't mean less story or less plotting; there's definitely a lot more going on in the story of XCX than Xenoblade. Also, XCX is about three times as long (at least my second playthrough of XCX at 160 hours, is 3X as long as my second playthrough of Xenoblade at just under 50 hours).

XCX is the largest and longest game of every Takahashi game, and Nintendo thankfully gave him the budget for it.

I would love for Xenogears and Xenosaga to come to Switch. I would love, even more, for them to be remade for the console.

I need to invest more time into this series.