I don't really mind Amy having a temper in moderation, in fact I think it helps give her character and prevent her becoming too saccharine. For all people complain about her in Heroes I thought she was pretty decent in that title, since she was more just an ineffectual brat that everyone's willing to dish it back against ("Ya think this is a joke, ya lil' brat?!?"). It's only when they exaggerated her to outright feral 'everyone's afraid to drop a pin around her' levels I find her too obnoxious (eg. later Sonic X, Archie in places). I hate the sociopathic abusive girl archetype, but I think the temperamental haughty types are pretty amusing (I think Sally was much more vibrant when she was one early on for example).