I think this would be a good idea. I'm getting pretty tired of dragon soul and would love a change of pace. In addition to Heroic Ragnaros, we still have a fair bit of tier 11 that we didnt kill on heroic. Never even got a look at Sinestra, for example.
Maybe we could do a rotation of sorts. One week do like we are now, progression DS. The next, burn through DS on normal (maybe Morchok and Ultraxion heroic, we seem to be good at those, mostly) and then head to one of the older instances to work our way through those heroics. Given that we only raid once a week I'd be cautious about dropping DS entirely for a week or more, but doing something to change things up would be a good idea, as we probably have three or four months at least until MoP. And the truth is, we are all geared enough such that we can kill anything in the game right now. More stuff would be really nice (caster trinkets, spell dps dagger, yes please) but we can progress without them.
That's my thinking, anyway. Worth what you paid for it!