@Fatboi1
You seem to get what I was gettin' at, the most. I didn't want to type too much in the OP and wanted to get right to the point.
If you just have a shooter, yea', you can't sacfice gameplay too much and you can stick a simple story on it.
I'm just sayin'; games become that much better when the story is as good as
Mass Effect...
A game like Mass Effect imo has pretty much subpar gameplay but people rave over it because everything else is done pretty good. I was always vocal against the mechanics of the ME series and how clunky they were. I couldn't for the life of me understand how the gameplay seemed to be overlooked in those titles. ME2 and 3 has very unsatisfying mechanics at times especially the cover system but I digress.
...as for
Mass Effect; this game was ruined by two things:
Business Decisions and the implausible decision to change the entire way they wrote it,
to have two guys write the ending.
Mass Effect (1, 2,3) 's story makes it the best video game I've ever played. But, it suffered from trying to make sells.
It went from classic RPG to bang, bang shoot 'em up, linear gameplay. It never really grounded the gameplay, but, I do like a lot of the improvements they made. For example; I thought the first one overdid the weapon, ammo and armor customization. But,
3, kinda streamlined it too much.
I didn't mind the cover system and subpar shooting mechanics, because the variety and environment made it fun.

Try to kills those bashees at the The Ardat-Yakshi sanctuary

ANYTIME you have to fight husks
But, that's the best example of what I was gettin' at; my favorite game of all time was a 5/5 on story, but, 3/5 on actual gameplay.
The 3 games, in the OP, prove to me, games can survive on basing it on story progression, not combat and skill building.
The actual gameplay, in those games, aren't bad, just scaled back to present the actual as the lead singer.
EDIT: Also, I think multiple ways of interpreting the ending v.
"alternate endings" is the best way to keep people invested in the game.
I think a story has to be grounded and basically limited. I still wondered what exactly else ppl wanted to do with the Reapers at the end.