I'm weird about this. To enjoy a game to its fullest I need ONE character (at least) that I simply adore. The more the better. If I have that character I can put up with characters I actively dislike, bad story, and subpar gameplay much more. Unless every single other character was just awful.

If I don't have that one character and the cast just doesn't move me, it does hinder my enjoyment of a game by a good bit. Doesn't mean I'll dislike the game, but it'll never reach full potential for me.

Like Final Fantasy VII. I like Red XIII but I didn't love him. I didn't mind a few of them. I actively disliked a few of them. So because of that, I will never like the game as much as some others with worse stories and gameplay. Bravely Default had excellent gameplay and an interesting story but I didn't care much about the cast and so it ranks below games that are similar but not as well executed, all because of the characters. Xenogears has an amazing story, probably my favourite of any video game, but I didn't care much about the cast and so it overall ranks pretty low when compared to games with less interesting and well told stories.

I still like all of those games I mentioned, I'll still play them again, but I'll never like them as much as I could have