The look he had in the WHC picture is the best for him imo. Right now his beard is overgrown and his hair looks unkept and unwashed. I think he's growing his hair and beard out for his gimmick, but I think he'd be better off buzzing his head and keeping his beard in check just do he looks more presentable.
Re: Daniel Bryan needs a haircut and trim his beard.
The beard works because kayfabe wise beards protect against strikes to the face somewhat, in that they don't hurt as much, supposedly. Also, the idea is that he's a bit of a mental case, a bit of a loose cannon, so he dosen't shave.