I just wanted to let nick learn whats it like to be in clyde's shoe for once. Thats the only thing missing from this movies. Gerard's performance is outstanding and jamie fox did good. Its not that nick had to die or suffer but he needed something more drastic happen to him to push him even more to motivate and crack the case.
The most sad quote of the movie and the whole point of clyde's motive is that nick didn't even care and tried to bring justice for clyde's family. If nick tried and lost, clyde said he could have live with that.