What if a photon torpedo in TOS is either the dense laser burst suggested above, or a spherical casing keeping matter and antimatter in suspension, sort of like the antimatter bomb in "Obsession" or the mortars in "Arena"? The laser burst goes at warp one but can only go where it is originally aimed. The m/am cannonball is sublight but can adjust course in transit.
Then some genius invents a warp propelled casing - the TWOK torpedo - and the new ship's design is adjusted to allow for the more extensive launchers needed to handle them.
In such a scenario the number of torpedoes carried depends on which torpedoes you mean. Laser bursts? Almost unlimited. Cannonballs? A hell of a lot. Warp torpedoes? None in TOS but some limited number on the refit ship.
