I think it's fairly reasonable to assume the top Imperial Fleets are going to have the following configurations:

VSD II

Gladiator I (Insidious)

Gladiator II (Demolisher)

Tie Screens

-or-

VSD II x2

Heavy Tie Bombers

Heavy Tie Screens

-or-

Gladiator II x2 (one Demolisher)

Gladiator I (Insidious)

Tie Bombers

Tie Screens

These are likely the builds Rebel Fleets will likely have to learn how to fight, so it's important to look at building something that gives you a reasonable chance to defeat each of these. May the Force be With You.

I also think we'll see

Victory

Gladiator

Ships Swarm

Ships are great but they are not the be all end all of the game. If they can be kept alive for 6 rounds you don't need three ships.

Moreover I think that's worse for rebels to play.

Tie Screens are great but Fels-Advanced's is just super nasty.

You may be more likely to see the generic "Tie Swarms" as going for two different things in the same list: one swarm to simply stall other fighters and another swarm with Major Rhymer to be a dedicated ship attack force,