Rayquaza has plenty of chance to be a heavy hitter in the upcoming format with the Eelektrik energy engine already being popular and the fact that it can be paired with Raikou EX ( which evidence has already shown will see play) and both have free retreat under Sky Arrow bridge.
also his damage output is huge 3 discarded for 180 and the ability to pick those energy's back up next turn.
Put simply Rayquaza EX = smart investment
Personally i want to be able to grab an early pre-order on this if its at all possible