Sadly all games from last gen and onwards are ticking time bombs with patches required to make them work correctly lol.

Most of the time with MP games has the majority of it's play at least 3 modes with the core game modes being TDM, DM and Capture point, With Overwatch and TF2 we have Payload.

I'm not sure about cutscenes, too many ends up cutting into the actual gameplay itself or dragging it on like with Star Wars Battlefront and the AT-AT shooting down Rebel ships with the slow cutscene playing out for each loss/victory.

Most MP games these days tend to feature unique customisation one way or another via skins, insignias, colours, clothing, weapon loadouts etc.

The SIm/Skyrim approach isn't really meant for absolutely every MP game in existence though, to expect that for literally every MP game is like doing away with MP games in general and what unique elements they could offer, not to mention that design would easily clash with games that don't adhere to size/body changes, imagine Titanfall where I make a really tall fat character and then he meshes into the cockpit and ends up sticking out like a sore thumb. Now I could imagine you saying "well adhere to that design", but the fact is that would require more work to make sure every body shape and size fitting absolutely everything in the game and noit all devs want to go with that idea and I can't really blame them as it's not something that fits with everything. Also we don't complain about that system lacking in games with featured characters who have already been designed for you to play as.

With a completely made up average joe character, I honestly cannot imagine there being any worthwhile backstory to make up, even for an MP only game where it's not about any sort of story and you are going to fight against other players or co-op against AI. DOOM's SP campaign is so simple for a backstory but the majority play the game for the gameplay and slaughtering Demons, not figuring out the age old history behind the yellow and blue keycards or average worker #56 who's corpse you just removed from the desk to hit a switch. With Star Wars Battlefront we are Rebels vs Stormtroopers in modes that involve destroying two AT-AT's, there is no story behind that, nor is there one needed because we know why we have to kill them and that's without backstory since everyone on the battlefield is no one special besides the one time heroes someone can play as. 

TF2 actually has a lot going for it if you went back tor ead the lore behind the characters, watch their intros and learn about who they are through the comics, why the mercs Red vs Blu right against one another and why Saxton Hale does what he does, all while Gray plots to end his two estranged brothers in order to take what he wanted from them and the Australium. All that from an MP only game and that was Valve dishing out comics/movies over the years along with the intro vids containing little nods and secrets for fans to figure out, the same is already in motion for Overwatch abd Blizz clearly is taking notes from Valve on how to present and layout their game to their audience.

No game is ever perfect tbh, just like nothing in life is and how we are a flawed species. You say something is perfect and I could easily disagree.

In Titanfall's case. The exterior mech model, auto scales characters down. As they jump in. To fake it. For interior shots. They can have seats that are bigger/smaller, and can be positioned further back, or closer . To accomidate tall or fat characters. For clothing etc. It's a game that is missing SP. You have the time to work on the characters model issues, now. The cockpits default designs and size are premade to acomitdate a person, if made max fat and max height. That's the easiest way to deal with that.

Because the servers are gonna shut down at some point and we won't be able to play games we bought for 60$ anymore (Online multiplayer games)

multiplayer often give more playtime as singleplayer so it should be ok, even at full priece.

You're still asking for a design change that not every SP even follow and it's always down to time, money, optimization and fitting their overall vision.