1) is cruel- sends girls to be raped/killed by Qyburn.
2)is dense/stupid - reinstates faith militant ignorant of what that means for the crown past and present.
3) is delusional - I'll be a better ruler than tywin, better ruler than any king, you'll all see!!! It's only cause I'm a woman!! :' (
4)surrounds herself with sycophants, yes men, and imbeciles
5) has no judgement and is ruled by her own capricious impulsivity - takes Joffrey off the battle lines, defers all the debts to the Iron bank causing economic chaos.
6)is neurotic and has inflated self worth - the tyrells are out to get me!!!!
I think that's enough. I can't imagine anyone being "Team Cersei" ...especially in her confrontations with Ned, that's like rooting for the emperor during star wars or something.