I think its actually a good thing at present because there is clearly a design space for such a ship. Whether it comes as a rebel flagged quasar (Sullustan Liberator cruiser from Rebellion game?) or some other sort of ship, clearly the designers have a strong ship role they can use at some stage to round out the rebels.
I honestly can't see where the threat of "OP" is. Rebel squadrons are generally not hitting as hard as Imperials at present yet cost more. Imps easy access to swarm, character buffing, black defender dice etc, not to mention the Saber/Valen/Marek/Jendon build and relay 2, are all devastating against expensive rebel generics. Whereas rebels depend on blue dice with only a few options for rerolls (basically Toryn). So Imps find it pretty easy to get 3 damage reliably, which is what you need against bracing aces, most rebel fighters struggle.
