Want a competing conspiracy theory for your "bannings were just to make people play WoW"?
(which by the way makes no sense since the people who play D2 and were going to play wrath would likely have done it anyways, and the ones who weren't, still won't)
They're working on development of starcraft 2 and diablo 3. Both of which are promised to include battle.net play. It would make sense as part of their development that blizzard would be looking to improve on their battle.net architecture including their hack combatting methods. Using the existing diablo II and starcraft playerbases which are "not quite" dead as testbeds to develop different strategies for their upcoming titles would make sense would it not?