I truly don't think there's anything wrong with saying "You're awesome but we're not really feeling connected and we think this isn't quite working for us." Breakups happen, I don't think they're really any different in poly than in mono, so you can probably find helpful resources just by doing a general web search. As long as you're kind about it, I certainly don't think you're violating the campsite rule.
I don't see much reason to give her a list of the problems if you truly have no intention of trying to make it work -- I think that would send a mixed message, like maybe she would think that if she just was a better guest it would all be ok. Maybe if you all stay friends, and she wants to talk about it further down the line, when there's more distance from the situation, you could dissect the disconnect then.
All that said, if the sex is great and no one is in emotional distress over anything and she's just a little inconsiderate, why *not* try to work on it before cutting her loose? You should feel absolutely no obligation to do so, but I'm just not sure why you wouldn't... not every connection needs to be a deep, romantic, forever-love (of course, your feelings may vary on that score, some folks truly don't like fwb's), and maybe she could really reform her habits and be a better friend if she understood what she was doing that was irksome.
The major players. Me, 30ish bi female. Gia, girlfriend of 4+ years. Clay, boyfriend/dom. Davis, ex/friend/"it's complicated." Eddie, roommate & fwb.
The supporting cast. Eric, Gia's husband. Bee, Gia and Eric's toddler. Dexter, Gia's lover. Helen, Eric's lover. Izzy and Nikki, Clay's partners. Liam, Eddie's husband.