I think that's it. He doesn't have the grounding in the basics that players who come through an academy will get. Particularly on the tactical side of things. Doesn't mean he can't learn them still but he's a few years behind.
25, but I'm terms of football experience/development probably more like a 20/21 year old.
Warnock should be far better for him than Woodgate, think he needs an experienced manager. But worth persisting with, as he's capable of things many other midfielders at this level aren't. Just needs to work on the basics a bit.