I'd have to agree, it's really not as bad as it seems. At this point, I think of T&C as a niche "active mitigation" ability that we have, since SD and FR are supposed to be the main ones. For bats on Tortos and trolls on Horridon, SD and FR will do the job completely without the need of T&C. Still, that doesn't mean I completely ignore a T&C proc on those encounters with those specific tanking jobs. On Tortos I'd just apply T&C to Tortos whenever I get a chance to help out my tanking partner, and on Horridon I'll still use it on adds for extra DPS and survivability (and eventually on Horridon, as I'm a full-time adds tank since I control them the best /flex!).
I don't want to completely derail this thread, so I'll come back to armor. Unlike T&C, armor is universally helpful on all encounters for all tanking jobs you may have, which is why it's the prime candidate for a fast Guardian adjustment (plus, maxmizing T&C use is really gear/skill dependent, adjusting it now to improve Guardians this current tier would likely not help the majority of the population and/or take too long to implement).