Back when the Jays traded for Happ, Jon Hale identified a possible issue with curveball overuse and that the Jays might have traded for him with the intention of fixing it. http://bjays.wordpress.com/2012/07/20/new-blue-jay-j-a-happ-is-overusing-his-curveball/
I can see the reasoning for acquiring Happ. The bigger problem was that with his arb eligibility he wasn't quite cheap enough to be an attractive project. You can find pitchers you want to fix for cheaper. That being said, since he's here, I have no real issue with him being a top candidate for the rotation. Before spring training, I would have went Happ/Redmond on paper. Now that Hutch looks like he might be all the way back from his injury and Happ doesn't look sharp at all while Redmond does, Hutch/Redmond seems like the obvious configuration but it's still early. The more pitchers pitch well the better so despite what Gruber92 says, we really should be rooting for Happ to do well. If nothing else it increases his trade value.