I think the LIs' designs are more important to me - it's what I'll be looking at for most of the game, after all! Although I still care about the MC :)
I am playing Reine des Fleurs! I really wanted to play it for a long time because it looked so beautiful. I am half-way through the game and while the plot isn't always the best, I'm still having a good time :)
Art style is incredibly important to me. I probably won't buy a game if I don't like the way it looks.
Sometimes I feel really bad because of this because I rarely pick up Western otome :( I just don't like their styles most of the time.