Although it's yet to be confirmed by the movie people themselves it seems promising.
(this pic was posted on Twitter of Jamie trying out for the role)
I think Jamie is a talented actor who can adapt to which ever role hes playing. In the past hes been seen in:
I understand some fans may have had another "Jace" in mind but we should all get behind the Actors chosen and the movie making process, so it can be as successful as it can (and should!) be.
We need to put our faith in the guys making the movie.
Congrats to Jamie and I hope he does the TMI books, fans and Cassie Clare proud.