Personally from the description and designs I've seen on the Akira, i'd consider it more of an Escort Carrier. It is no where big enough to be considered a complete fleet carrier and it has quite a heavy arsenal of weapons for it's size.
This is of course what makes it my favorite. Always liked the escort carrier concept. Used it in other games whenever I could. Pax Imperia 2 for one is excellent at allowing you to outfit Transports or Cruisers as escort carriers. Concept worked well. Gave you cheap to build and maintain warships till you could conquer enough planets to afford developing large fleet carriers and battleships. It would also trick the AI into attacking as it would think its an easy target. Then you could suddenly unleash hell and wipe out an entire fleet. Would also make good planetary defense fleets as the AI would instantly target the weaker ships. So you could setup a escort carrier fleet at a fortified frontline world and just use it to burn fleets while your main battle group assaulted systems.
Sigh...I miss Pax, nothing has ever been made like it. Everything nowadays is just too much micromanagement of empire systems or too simplistic in graphics. Gratuitous Space Battles comes close but the ship designs and combat is lacking. Also rather mindless in concept.
As far as I know, Akira class vessels were your standard line cruisers during the TNG timeframe. With their refit, they were supposed to be on par with a Galaxy class cruiser as far as combat. The main difference is the Akira lacks the sensors, lab space and crew compliment of a Galaxy. It's powergrid is also not as beefy. It was Starfleet's first real "warship".
At least, I think....
Unfortunately we really don't have anything cannon to back anything that anyone says about it.
It is never mentioned to be a warship, nor even comparable to the Galaxy class in anything.
The model seems to indicate that it was originally a carrier that then became a torpedo boat.
(The model seems to have a flight deck that extends the length of the ship, and she is loaded with torp tubes.)
But on screen we never see either role fulfilled, and she appears to just be another cruiser within the fleet.
Albeit an incredibly large cruiser.