Can't comment on the Knaresborough and Harrogate scenes, but I've been in York for nearly 10 years now. Initially it felt like a bit of a backwater compared to the South Lakes where I was beforehand. Things have improved massively with the new wall, but it's not Leeds or Sheffield and never will be. As seems to be the case with a lot of newer walls, a lot of the people that climb there have never climbed outside and probably never will. Also, it was overly busy, but the recent extension has solved that. The problems are well set by a variety of setters and change frequently enough to keep it interesting, plus the training area (2 boards, campus boards, bar, weights) is developing nicely. From York side of Leeds, it's easy to mix it with visits to CityBloc (or Depot on weekends).
In terms of "proper" climbing, there's a decent group of keen sport climbers, regular cars going to Kilnsey/Malham. Similar with bouldering through the winter, although it can be difficult to drag people away from Almscliff/Brimham/Caley to try somewhere different. Hard trad climbers are a bit thinner in the ground, but there's a few keen folk around.
All that said, I'm in the process of moving to Sheffield - mostly life related, rather than climbing related, but the benefits from a climbing perspective are obvious! Feel free to send me a PM if you want any further info.
