I used to think this as well, back when I first started playing WAR. If you're activating it in reaction to the cast bar for the tank buster, it definitely is harder to time, because it's a GCD ability, unlike every other mitigation ability (it's also subject to pacification, but that's another story). What I didn't realise, at the time, was the importance of a cooldown's recast. If you pop Rampart/Shadowskin/RI about 18-19 seconds in advance of a tankbuster, then you shave that time off of the recast.
This becomes pretty useful when tanking fights with a damage type that your job doesn't specialise in (i.e. PLD on magical fights, DRK on physical fights). As long as the interval between tankbusters is greater than 35 seconds, you gain an additional use of Rampart/Shadowskin. Making efficient use of your long recast cooldowns in a rotation is actually significantly more technically challenging to do. You should never really be waiting for the cast bar.
IB is a bit of a crutch, and it was actually a bit too versatile. I suspect that part of the reason that FC was introduced was in part to discourage its use, and I wouldn't be surprised at all if it received a more direct adjustment down the line.
Edit:
I've seen suggestions for a Intermediate version of the Beginner's Hall. That's something that could be useful, if designed with player feedback. The problem with tutorials are that they are an open loop design, and real players will always have an easier time troubleshooting exactly what you need to work on from watching you play. It's fairly straightforward to "spectate", if there's a player you want to study. Guides on fight-specific optimizations are rare, but you can figure out quite a bit by watching someone play.
They could also modify the GUI to help players track things like buffs/debuffs/DoTs. That may also emphasise their importance to newer players.