My thoughts and concerns on any potential subscription/payment model:
(this assumes any major changes probably CAN'T be made to the existing F2P system that was in place when the game shut down)
-We absolutely need free/trial accounts in some form. So many potential new players have expressed interest in trying the game should it come back, but asking them for pay to try a 10 year old MMORPG in this oversaturated F2P market is an unessisary roadblock to adoption.
-I think everyone who pays a one-time fee (say $50) should be set to Premium status, as defined by the old system, and immediately receive their 87 Months of Vet Status, all costume sets, power sets, Origin packs, Going Rogue and access to Pretoria. This is only fair to people who spent so much time and money back in the day to get some of it back at a reasonable price.
-VIP status should also return for players wishing to support the game monthly. My concerns are two-fold, however. First, I fear the returning number of paying VIPs will not be enough to keep the Incarnate system afloat; I don't think we'll have enough people willing to pay monthly to reliably fill Incarnate trials. My other concern is that many of the perks of VIP status are now moot (Access to Exalted, Priority server queueing, Premium in-game customer support ).
-With Sentinel not on the table, I think the potential new owners of the game should consider using the admin tools to instant level a number of trusted community members to 50 and kit them out so they can begin to float the AH economy, assist new players and in general round out the population so everyone isn't clustered in Atlas/Mercy/NP the first week.