Have you read the hosted game The 3Games? It has preset characters (the player rotates through I think five of them), and if I’m remembering right was pretty well received, and if you’re thinking of doing a locked character with this type of game I’d say it’s recommended reading
There was some discussion about a similar issue on another thread here First Person vs. Second Person that starts about whether to write in first or second POV but also discusses how much players will tolerate a “pre-created” MC, that you also might want to read through, although there the discussion was more pre-set personality traits rather than an actual fully-formed character
I second everything @IvoryOwl has said though–like you said in your post, people are already somewhat divided on the acceptability of genderlocking in games, I think this might not necessarily be the place for a game with a fully-formed character. It sounds like a lot of the things people love about these games, that IvoryOwl listed above, are things that you would remove. I especially also want to highlight @Mewsly’s comment–forcing the player into liking another character is pushing it, and I think would alienate a lot of players
(Edit – this was intended to be a reply to the whole thread, not @IvoryOwl specifically, sorry)