Since ENT's weapons placements, I've always kind of enjoyed the notion that the TOS Enterprise had tubes and phasers in comparable locations - aft torpedo tubes could be spaced on the rear of the lower saucer in such a way to have an (admittedly limited) aft firing arc. Surely, though, torpedoes are the more long range weapon, and the further away you are, the easier it is to line up your firing path.
In TOS, I don't that was the case. When they were chasing the Gorn in "Arena", phasers were the only weapon considered and they were out-of-range at 0.04 LY distance from each other. (And they did use photon torpedoes earlier against the Gorn in orbit.)
The other thing about torpedoes in TOS was that compared to phasers, they were kinda weak. If the Enterprise's shields could take the equivalent of 450 torpedoes before going down ("The Changeling") and the "starship equivalent" phaser attacks from the Orions only needed 4-5 hits ("Journey to Babel") that would say that phasers at full power are much more powerful in TOS.
DS9 seems to carry this forward somewhat. In "Tears of the Prophets", one of the few times we see a bunch of different class of ships firing on the same types of targets we see that 2 phaser hits from an Excelsior did the same work as 3 photon torpedo hits from a Galaxy-class. TNG I think flipped it around though and made photon torpedoes more powerful...IIRC.
Maybe, or the more simple answer.. Kirk almost never ran from a fight. So he had no reason to ever use them.
Heh yeah. Although in "The Changeling" they fire their forward tube at a target on their back quarter, bearing 123 degrees.
If I were to put a rear tube on the Enterprise it'd have to be on the back of the engineering hull, probably between the rear phasers.
The Reliants though just seem more roomy and modular/flexible. They might not be fast, but flexibility goes a long way for longevity, IMHO.