I'm not sure. Houston would have the potential to be very good defensively with Smith and Asik protecting the rim....even with the liablities of Lin and Harden on the perimeter. And I don't think the pairing would work on the offensive end at all. I'm also not sold on Harden being the primary scorer for a championship contender despite him having a very good year.
I guess my answer is sure, they would contend in the sense that they would have a respectable record and make the conference semi-finals every year. I don't think they could beat OKC, San Antonio, or the LA Clippers, and, if they somehow did, I think the Heat would be a nightmare matchup for them.
Quote from Davcicic: "I love the Magic so much that I would take them to the back of the school and get them Pregnant!!!!"