Yes, you can play the game in Tactical Mode only, if you disregard standard attacks and defensive maneuvers. What I mean by that is by not using shortcuts at all, you're effectively playing in Tactical Mode only. And if you know the game already and know which shortcut setups work for which areas and bosses, you can play the game by never using Tactical Mode at all (if Limit Breaks and Summons can be slotted into the shortcut menu, that is.)
Still, those are deliberate choices and you're most likely limiting yourself a little, so a mixture of both becomes more feasible. So in practice, you can probably choose which option you'd like to give priority to.
Thinking further, as you most likely can only heal or buff yourself by using a shortcut command, you won't be able to target another character than the one using said restorative or supporting ability/spell/item, severely limiting your options. So I guess you can only REALLY choose how to play regarding direct offensive strategies.
And that's where my train of thought reaches the terminus. Let's go bomb some reactors!