So a popular theory on the forums is that FFG puts small hints in their releases as to what they're releasing in the next wave. Ex: A TIE Bomber (w3) on the Homing Missile (w2), The YT-1300 (w2) on Swarm Tactics (w1), references to an advanced starfighter (TIE Defender, w4) in the Imp Aces (w3.5).
So, looking at the TIE Defender release, we see the Predator card. The Predator card has, in the background, the Providence -Class Carrier/Destroyer (courtesy of Wookiepedia: http://starwars.wikia.com/wiki/Providence-class_carrier/destroyer ), as seen in Ep III.
Thoughts on seeing Pre- Galactic Civil War ships in wave 5? I know there's a huge wave 5 thread that I didn't wade through, so apologies if i'm rehashing stuff here.
Also, I'd like to note that there's a lot of things I'd like to see from the Galactic Civil War still. Skipray Blastboats, Preybirds, Star Vipers, and a couple of the other YT Variants. Especially the Skipray.