In terms of skill, I hate OP/super smart MC. Like in many games I've played, the MC is like genius programmer/hacker. While it's fiction/fantasy, I hate when it's too far from reality. There always a trade off in real life. You're a smart hacker, you have no normal life. You're great at socialize with hundreds of friends or have ladykiller's trait, small chance you're good at things that need a solitude life like programmer/hacker/gamers.
In terms of characteristic, I hate when they're too naive/kind or too slutty/pervert/evil. But also it's boring when the character just straight normal. For me, the best setting for MC should be either 1/4 or 3/4 on pervertness or kindness/evilness. Let the NPC who had super weird/flat normal characteristic.
But you can scratch of all that, by render the game with the best of the best setting, as majority people just tired with shitty image. If you do that, you're game start with 60% approval. Then ... story, model, dialog fill the rest 40%.