"Fairly frequently" is one thing; point is, the firing rate normally achievable from, say, High Yield should be the torpedo's DEFAULT setting. Or, if it is not, the weapons should do a hell of a lot more damage than designed.
This is case where the Needs of the Balance outweigh the Needs of Logic. STO basically nerfed the torpedoes to make them less effective, because if they really did what they seem to do in the show, nobody would ever use phasers, you could literally just bury your enemy up to his neck in photon torpedoes (the fact that their firing range is identical to phasers is another feature of this).
That's just it, though: when you measure damage per second, you find that torpedoes and phasers are actually (for the most part) kind of a wash. Torpedoes DO more damage to a particular target, but they take a lot longer to HIT the target; by the time your torpedoes impact, you could have put four or five phaser beams into his hull doing the same amount of damage. The main -- in fact, ONLY -- advantage of torpedoes in game is actually the fact that they can do impressive damage to the target without having to divert all of your power to weapons. This makes torpedo builds pretty robust since you can transfer power to shields or engines when you need it without sacrificing attack power.
That, again, is a feature of the game trying to balance different play styles and make them equivalent when ordinarily they wouldn't be. The canon depiction of torpedoes and phasers has a similar but unrelated problem: photon torpedoes are not, it seems, a great deal more powerful than phasers and are essentially interchangeable with them in terms of damage yield. Here again we have the issue that, except for their possibly having a much longer firing range, there doesn't seem to be a REASON to include both types of weapons since they both do pretty much the same thing. Unless, of course, torpedoes have the advantage that they can cause a lot more damage when your phasers are starved of power (TMP, TWOK and TUC sort of imply this) but that would make photon torpedoes a kind of backup weapon for when the phasers -- their main weapon -- aren't working or need time to recharge.
On the other hand, it would be interesting if we had Star Trek -- both STO and TV -- actually flesh out the logic of these two weapon systems. If, for example, deflector shields are pretty much immune to phaser strikes and you have to use photon torpedoes to take his shields down; your opponent will try to shoot down your torpedoes with HIS phasers, but if enough of your torpedoes get through, his shields will overload and he'll be forced to either shut them down to save his engines, or use what little power he has left and run for it. If he chooses to stand and fight, now you have to close the distance to get into phaser range and risk getting YOUR shields knocked out by HIS torpedoes. So both combatants now have to be smart about how and where and when they fight.
Otherwise, it's just a slugfest with cliche videogame mechanics and the only tactic that matters is "shoot him till he's dead." If they're going to go that route, then there's no reason for torpedoes to even exist.
