Some very superficial research has turned up the following:
A US Navy
Arleigh Burke-class destroyer displaces anywhere from 8300-9200 tons; a US Navy
Perry-class frigate displaces 4100 tons. Now, this is just for the US Navy, it's of course entirely possible that other countries are doing things differently.
I think it entirely likely, though, that the people at FASA knew less about naval nomenclature than you, Marauth.
(No offense intended, BTW.
)
As for the pods on the New Orleans... I do my best, as a Star Trek modder myself, to shy away from the temptation to create uberships. I firmly believe, for example, that all that stuff added to the Soyuz is sensor equipment. In the case of the New Orleans, however, I had to go with the pods being torpedo launchers; and it was mostly because it looks so darn cool.
Especially the time I did a fanboy refit and made the bottom pod into a quantum torpedo launcher...
My justification for the pods being torpedo tubes runs something like this: I see the New Orleans as being a sort of "half-scale" prototype for the Galaxy class, and given its layout, there's really not a whole lot of room for a forward torpedo launcher. Maybe, in the optimism of the 2330's (when I figure its design probably started), the designers simply didn't give it torp launchers. However, when the
Rutledge (allegedly a New Orleans class according to the Trek Encylopedia or something like that) got toasted by the Cardassians at Setlik III in 2347, a crash program to add torpedo launchers might have been initiated, and Ambassador-type photon launchers might have been mounted in the pods to improve the class's firepower. I use this version of the N.O. as a corvette in a mod I'm working on for a game called Cataclysm (using, BTW, models made by the Star Trek: Homeworld team, some of which have been drooled over on these boards of late
), and it's a LOT of fun to watch in action.
Not saying that any of this is "right," just giving my personal take on the ship...