I can only speak directly on behalf of those who I've spent lots of time with in game. My somewhat large FC has had many great times -- none were in Diadem.
Well, my current playtime is: 692 days, 17 hours, 30 minutes (I'm achievement collector). And I absolutely hated like 95% of it.

Anyway, 100 pages of concerns, suggestions and even instructions "How to". And still no official reply. Great. Just great.