I'm loving this Barret, but I feel that he looks too calm.
The original texture and concept art show him so angry, that his eyebrows are practically melting into his eyes he's frowning that much. xD I think altering the eyebrows so they match the same shape and position of the original eyebrows can make all the difference. Also, I agree with squall, though I don't think it's the fact that he has big lips but more the fact that they seem too 'defined'. Same with his cheekbones, the highlight looks a little awkward. Try smoothing those parts out and I think it'll start to look a lot closer to the original concept art.