This is a topic that could get the discussion going around in circles. With that said, here is my take:
In a twisted logic sort of way, getting Gamma back is like getting new content, except it's just a revamp.
I think this would be good. I was in A.S.S. corp and had to take a long hiatus due to work demands. Before I left, as a corp, we were heavily involved in building up the Gamma base on Novaya Trava (IIRC). That was immensely fun and provided a focus and direction for cooperative game play. I particularly liked the group beacon pit events. But whether or not we mined, harvested, or blasted NPCs for recyclable trash loot, most resulting resources went to building up the base.
I think the return of Gamma islands would allow this again. I just hope such a land grab would not be dominated by the power blocks... I agree with those who have said that the Gamma issue should have been resolved before STEAM, which in my way of thinking, makes it the highest priority for Dev time.