Doubt it'll be a straight rollover based on 2015/16 status. Though they'll have to make some sort of announcement by mid-2016 when the deal closes what the qualification criteria for 2017 status (likely the first year of the merged program) will be. As with merged FF programs, nights earned in each program would be added together to determine the following year's status.

The stay vs night criteria with SPG is the major difference in aligning tiers for all other than SPG Plat+ (75K nights+). And the conversion rate of SPG:MR points similarly would have to be aligned...I can't see 1:1 since one earns 2 SPG points per $1 vs 10 MR points per $1 on stays, plus elite tier bonuses in both programs. So SPG points will have to represent a 1:5 conversion for any points requirement for lifetime tier status. SPG will certainly have a lifetime points earning record so this should not be a problem.

But it does seem SPG Plats (but not Plat+s) will be the big losers, dropping down at least one tier. Lifetime Golds would go to Silver, but since there are very few benefits for SPG Gold, it makes little difference. I just want to keep lounge access as a SPG Plat, so could likely manage on MR Gold though not sure I can get 50 nights a year since I requalify for SPG Plat on stays. Though it might be easier given there are so many Marriott brands where there have not been Starwoods given my travel patterns. I've made those stays up with Hilton, Marriott and IHG properties so could likely come up 50 nights through 2016. Then again, will I be keeping Marriott Gold with my UA Gold status (dropping from 1K to Gold but still get MRGold) if there are no changes to those criteria.

Still, it's all speculation for another few months, so I guess we'll just have to enjoy our SPG status benefits through next year and see what the merged program is.