It is harder batting with the tail, which is what Shakib does all the time.
During the time he's been playing, Bangladesh has won 6 tests, out of the 41 he's played.
In the first, he scored two fifties and took 4 wickets, top scoring in the first innings. In the second, despite mediocre batting, he took 5 wickets. In the third, he took 8 wickets and scored 96 not out to win the run chase, taking man of the match. In the fourth, he was again mediocre with the bat, but took 7 wickets. In the 5th, he scored a century, along with two 5 wicket hauls, man of the match of course, first time anyone's scored 100 runs and 10 wickets since Imran in the 80's. In the 6th, he scored a 50 and took a wicket. I'd say he's had a few match winning performances.