I find it to be rather simple. One 2hr show. Seriously, think about it.
1. If TNA gets a seperate 1hr show, do you honestly think they'll use it as a heat/velocity equal? No. They'll use it the same way that WWE used Smackdown before the brands split up. With a 2hr show, they almost have to use at least the first thirty minutes for mid-card pushes.
2. With only 1hr at a time, their matches can't be as long. Last week had just one match, and while it was a good match, there was nothing else. With one 2hr show, you can have matches as good as that every week WITHOUT sacrifing the rest of the show.
To me, there's no contest.