Anyone wanting to fill their logbook with 30 seconds-long QSOs won't like QRP.
I don't know about that - it's easier for QRPers to make short contacts than longer ones due to changes in condx...QSB, QRM, etc. Maintaining a QSO for an extended ragchew while operating QRP is more difficult than making short QSOs IMO.
Contesters won't like QRP, though there are QRP contests...
That's certainly not universally true either. My background is primarily contesting - I've made a number of contest-expedition trips and have been part of multi-op teams working over 10k QSOs in a weekend...and I'm a big fan of QRP. While I do enjoy operating the occasional QRP contest, those really aren't like "real" contests such as ARRL-SS or CQWW, etc. - those are much more fun to operate for me, even QRP.