Well, now that Bendis is leaving, it's time to review his run as a whole. Personally I found his run charming but flawed.
Riri never seemed to be protecting anyone but herself. I also thought her grief over lost loved ones should have been much more of a living thing, rather than something that just existed in her origin and then never popped up again.
Nonetheless I found Riri herself quite charming and enjoyed the book, at least the first time I read each issue. In fact, I basically went through this cycle each issue: I'd read it, end with a smile on my face, and say to myself, "ah, that was charming. I'm glad I bought that." *fifteen minutes later* "it would be even better if it had some Doctor Who/Buffy style angst about dealing with grief and teenage issues, though"
As for who I'd like to see replace Bendis: I really liked "Penguin: Pain and Prejudice" and would like to see Gregg Hurwitz take a crack at The Mandarin. Stan Lee's origin for the Mandarin combined similar themes of an aristocrat being raised by someone who hated him, fused with X-23ish ideas of an indoctrinated super-soldier raised to be the perfect weapon of someone who didn't care about him as a person at all. Stan Lee's Mandarin basically starts out as sort of Penguin, moves on to sort of being X-23, and then ends as Christopher Columbus, all in the space of a handful of pages.
Gregg Hurwitz is, I believe, the perfect writer to take that brief little origin Stan Lee wrote and expand it into something really interesting.