This is likely to be discussed at some length in/by the motor racing fraternity..........., there are several possible reasons for the change (some good , some bad), but in essence changing the rules this close to the race sets a very unfortunate precedent. If as a result Rebellion were to get on the podium, let alone win, all hell will break loose.
I am all for close racing, but the main teams have designed their cars (to win) around the rules (assuming that they would be applicable in June) only to turn up and find the goalposts have moved.

Surely it can't be as cold a last year (had to forego shorts for jeans), although not the wettest!
Bring on the sun....