I don't disagree. Good force users can play around sentry pretty easily in most situations in order to survive.
There are situations where it would be strategic to be able to block oncoming fire for your team though. Capturing objectives and leading the way for your team in narrow hallways like the last objective on Kamino come to mind.
Sentry's ability and especially super charged and explosive sentry's ability to choke choke points is pretty extreme. A little more counter play available in the game wouldn't hurt, which is why I say it is health for the game play.
It also helps players who aren't that experienced have a little better experience with heroes. Not being able to block one certain type of blast fire when you can block the rest is un-intuitive and I can understand the rage.
