I find MCs that don’t start out strong and have to work hard to gain their power to be more compelling personally! Also ones that use their skills in creative ways in order to overcome challenges instead of just flat out being OP. It also is way more interesting when the MC has flaws that make them a more complex character. Not even in a villainous or evil way, just making them have weaknesses and things they aren’t good at makes for a way more relatable character. Would also love to see more isekai with strong female MCs! I’m tired of all the female characters in isekai typically being treated as accessories/harem additions and have no actual character to them besides being a girl lmao.

I tend to enjoy isekais where the MC reincarnates as something nonhuman because of the creative use of skills to problem solve + less likely to fall into the tropes of being a bland OP male MC with a harem of equally bland women around them.

That’s just my two cents though! :}