Virtually every job has damage windows into which to cram "anything and everything" and without TA that'd just turn into everyone else's 15 seconds buffs every other minute. Ninja will never not exploit damage windows to the best of its ability; every job is obliged to.

If you want TA to be a less invasive factor, that's just a matter of reducing NIN's ability to bank for and thereby exploit any and all raid damage windows. Such would be more helped by having a greater portion of CDs that would rarely sync to multipliers of 60, reverting Kassatsu to not give a free (non-charge-consuming) cast, or even by taking out our second charge of Ninjutsu than by removing TA.