I think i've decided on Science Captain and building for the Carrier on one character. I'll be a little gimped leveling up as i won't waste points in the various ship types apart from the first one that adds to Bcruiser and Carrier then the final Carrier one. They don't make a huge difference though as i went right through tier 4 with no points in the Vor'Cha and will mean i can put more points into the Operations skills to enhance the holds, debuffs etc. Might be a pain leveling the Battlecruiser with beams though as i had 1 heavy cannon, 2 banks and torps up front in the beta which did massive damage with the buffs but cannons are useless on the carrier so can't waste points there.
For a second toon i'll probably go Tactical and Battlecruiser fully as that was a blast to play, in prolonged matches i was very close to overall Bird of Prey damage numbers in the final scores. Plus ground PvP matches were insane as Tactical, i probably topped the kills in 90% of my matches with the amount of buffs and debuffs we end up getting there. not to mention being able to hit 24 seconds stealth right in the middle of combat.
Not sure what i'll use for the third slot, whatever it is it will be a long time before i level it up anyway so hopefully we have Romulans by then.
Edit - Just an FYI, Carrier gets 4 free skills that appear under your weapon window that enable your next attack to target individual systems weapons, shields etc. I didn't get that on the Battlecruiser so assume it's Carrier specific.