Yeah, since exceptional numbers of fighters would appear to be needed to pose a threat to another capital ship, the utility of such a carrier would be questionable.
To me, the big argument against ships deploying fighters this way is the fact that Enterprise-D didn't have any. With a huge main shuttlebay, if any ship was going to carry them, you'd think it would have been the D and her sisters.
The only fighters we saw were more like runabout-scale and appeared to operate independently (their being that size makes their necessarily significant warp capability more believable), and Sisko's "modified an old support courier" line or whatever it was, which would seem to apply to the reuse of this same model, suggests to me that they were modified ships used outside of regular Starfleet doctrine.
Ron Moore said in a Q and A that the inclusion of the Starfleet fighters was to suggest their thinking had been influenced by the recent Maquis activity, which would certainly support the idea of it not being a regular part of Starfleet operations.