Remember, too, "carrier" doesn't have to mean "Trek equivalent of Nimitz super-carrier".
15 micro-torp launchers doesn't give it any punch, and I'd think phasers would be better for point defense, anyway. The only way I can see 15 as not being out of line is if they're slow to reload, simple, robust, and stacked for redundancy. If it gives them the same output as most other ships, but they can lose more tubes before being unable to fire, then it's not unreasonable. If Jaeger meant that they really could fire 15 times as many torpedoes as anyone else, then I'd have to say that's unreasonable. If it fires *5* times as many torpedoes, then it's JUST a torpedo cruiser and can't be some kind of baby carrier in addition.