Considering her female status and the little time she got to be around, i think she's quite good.
Getting owned =/= weak. Sure she's apparently low on the Akatsuki ladder, but that doesn't mean anything. The fact that she has a place in the Akatsuki automatically makes her strong.
I don't see any problem with her romantic feelings at all ._. Compared to the likes of Sakura and Ino.
She loved Yahiko and Yahiko loved her back, there was no 'domestic violence' in between, coupled with submission on her side, and she cared for Nagato has a longtime friend and a partner, nothing weird about that. This aspect was very well handled imo.
I can agree that she wasn't very attractive, but Jiraiya's comment made the opposite a manga fact though >_>
I don't particularly like her, but i find her design very fine, and her backstory (even though sad) appeals me for the reality it portrays in real life.
She made me care enough for me to feel sad about her death though, so i could never say she's a bad character.