it seems that the training grounds isn't being utilized - will it return back to its former self or be left vacant like the Bazaar?
That would be really short-sighted. The word training implies that it is for less experienced players, and the current version caters to them. Right now there are very few inexperienced players, but any plan for growth assumes that such a population should be taken care of. It just needs some regular attention after the revamp happens so that playing fixed decks becomes as fun as custom decks and a little bit more gold incentive would help as well (if 1/4 of the campaigners started to play fixed decks we would have a seed to build a population from). An upshot of the current arrangement is that grudgematches are more prominent and that the casual-match abusers have nowhere to hide their shame.
