the rules always get changed in the middle of the game...that might be the only certainty in F1.
imo Merc just need to be given proper incentive and/or the proper leverage needs to be found to get them to change their position. and not just Merc, teams like Williams and Force India need to be given an incentive as well.
i suspect that a compromise will be found but it will be late in the game giving Merc and their customer teams a chance to build up some points for the early part of the season.
makes no sense to give the other teams the whole winter to catch up, no point in letting them bring updated engines to the winter tests...allowing them develop over the course of next season seems like a fair compromise to me...with the added bonus of giving us a chance to see in season development back in F1.