The framing of the regulations for this new era of F1 were developed to allow for progressive year on year development by the engine manufacturers, with in-season changes only made in order to save costs or improve safety. A system was devised in which the components of the powerunit were 'weighted' not by their physical weight but by their importance with items scaled 1-3:
As you can see this is far from the frozen development path that the V8's lived under and the likes of Red Bull and Ferrari would have you believe. Unfortunately someone at the FIA forgot to change the date in the 2015 Sporting Regulations, leaving the original homologation date and opening the door for the teams and manufacturers to intepret the rules as they see fit. With no re-homologation date in place both Renault and Ferrari have argued (succesfully) that as the weighting matrix (above) only stipulates 2015 as a point in which the 32 tokens can be spent they must be free to continue to develop their powerunit throughout the season.
Honda and McLaren seem to have come out as the biggest losers in the debacle, as Charlie Whiting's technical directive appears to suggest that as Honda didn't homologate a powerunit in 2014 they must do so by the 28th February 2015, and as the other manufacturers did in 2014, run a season whereby they adhere to no changes, having already had the artificial ability to spend their 32 tokens. I'd suggest that's speculative at best, as the regulations have that intent but aren't prescriptive, meaning that if Honda or McLaren put the lawyers on it they'd win hands down.
It's a half way house in comparison to the total tear up of the regulations that some had been proposing but it's still against the spirit of what the regulations originally intended, stunting the development curve of these units much earlier in their gestation period and changing the way in which the homologation and token spending procedures must be framed going forward.
What will now become extremely interesting throughout the 2015 season is how these developments are implemented and just how much the FIA will make publically available through the document system. In terms of transparency I feel that any changes pertaining to weightable items must be presented at each GP but we shall see if that comes to fruition. Furthermore as each driver is only allowed 4 complete powerunits in 2015 (broken down into ICE, Turbo, MGU-H, MGU-K, ES and CE) staging the 'token' spends will require careful planning based around lifing not just performance gains.
The sport once again falls victim to the very issue that has just led to the demise of two teams; cost. How ever you cut it, the cost to implement in-season development will cost the engine manufacturers more money and likely result in the units costing the purchasing teams more money too.
In terms of performance Mercedes were in a league of their own last season and although we know Red Bull and Ferrari are eager to make a dent in that with this latest movement of the regulations, we must also consider the fact that in 2014 Mercedes provided identical equipment to Williams, Force India and McLaren, all which were unable to surmount a sustainable attack on the works team. Therefore although the powerunit is an incredibly large part of their success it's one that has many facets, suggesting that Red Bull, Ferrari et al have more work than on their hands than simply finding a few horsepower. Even though Renault and Ferrari don't have carte blanche in terms of the in-season development they'd hoped for, they have won a battle in the war of eroding Mercedes advantage, yet they must remember that Mercedes have the same constraints within which to work too. Mercedes clearly had a designated plan with which to spend their 32 token allocation but who's to say they'd spent all of them developing their 2015 powerunit? They too may still benefit from the in-season development and pull away further still from the others.