In my opinion, he has a mental issue with T20 batting for some reason. Look at his only first class match, he scored 54 in his only outing. I think he needs to get set, and then he will become dangerous. He is no Tamim (I'm going to stop comparing BD players to other country players, well, I'll try
). He can't walk in and begin hitting boundaries. He needs to rotate the strike first, and then can he look for the ropes.
He should focus on his batting, as he is, and always will be classifies as a genuine all rounder. This means he has to perform with both Bat + ball. But when his bowling is good, and he is a teams best bowler, then you can't really complain, knowing the potential he has to destroy a team with his blade. I think that Vettori is someone Shakib should try (not imitate), but follow an example of. But I would take 4/31 and 5 runs any day.