I won't really mind that if they removed us and let us the player just watch the journeys of said characters than letting us create our own bland Mary Sue / Gary Stu MC if they're just going to focus on the others, really.
How would that work, though? You'd need some way to poke the characters and make them go.
I'd personally like it more if they just gave the MC a more defined character.
Like Shepard from Mass Effect. Created character, but definitely had more of a concrete persona to work with, and thus is a lot more interesting to work into the story.
The whole point of a blank slate is for you to fill it in. The appeal is creating a character to go on this journey, making choices that shape the character, and at the end of it completing an unique character. Are they a hero? A villain? A paladin? A scholar? A thug? A lech? An average person? That's for you to decide. That's why people get upset when choices are taken away and when they force dialogue upon your character that doesn't fit them. You don't have to self-insert but the point of a RPG is that you're suppose to create a character. If you find them boring, then that just mean you didn't put any effort into creating them.
I get the point of a blank slate character, I just don't think they work well in video games.
I used to play a lot of tabletop RPGs, where you actually start with a blank slate and can freely create and direct your character. That kind of freedom simply isn't possible in a videogame. That kind of character in a video game isn't really "yours", their actions are predetermined from a relatively short list.
I just don't feel any videogame is immersive enough to really roleplay a character that truly yours, which is why I prefer Geralts and Commander Shepards and such.