The Caitain Carrier will not be released anytime soon. Al talked about it but now that he is leaving STO we can not be certain that it will be released at all. I heard in a podcast from him that he wants to also do an Andorian Escort and a Caitain Career the idea is that it will not be a Federation ship but a ship from one of the federation members more in likely the Caitain's. Now that CaptainGeko aka Al Rivera is leaving STO not sure if those ships will be worked on the only non Starfleet Ship in the game is the Vulcan ship.
Only 1 race i know of had a carrier the Remans but if you are waiting around for the Romulan/Reman faction it should be out in season 25 using the current rate of development in the game. I am also told in season 26 they will fix ALL of the bugs they create in the previous seasons.
I don't know about a full sized carrier, but I really thing Cryptic should stress the size of some ships shuttlebays. In some instances throughout the Trek shows and movies, I have seen up to 8-9 shuttle in a shuttle bay at one time on some ships. In my opinion, you should be able to decide what small ships you can put their, and be able to call them in when you need to.
For example, if you have 4 runabouts in your shuttlebay, you can call in 2 to help. It's like your carrier idea, but fits the Federation in a much nicer way.
Carriers are comming in season six / sometime in july, according to a dev post & interview. No, not that Caitian Carrier, that was meant as a joke I believe, maybe not, but regardless, haters gonna hate. Feds get carriers, deal w/ it.
Its not exactly true that its non cannon for Feds to have carrier ships technically the Akira is a carrier. Thats why it has the front and rear shuttle bays to quote -Alex Jaeger of Industrial Light and Magic (He designed the Akira) "This was my gunship/battlecruiser/aircraft carrier. It has 15 torpedo launchers and two shuttlebays – one in front, with three doors, and one in the back. I really got into it with this one, with the whole idea that the front bay would be the launching bay, and then to return they'd come into the back, because they'd be protected by the rest of the ship."
That is not to say they will release carrier ships. I do think it would be cool if they released an Akira variant with the capability of launching fighters as a C-store for Vice Admiral (because its supposed to be a carrier anyway). If cryptic wants to keep carriers as a type of ship only allowed for klinks I wouldn't object though its good to keep the factions different IMO.