It was suggested in another thread that Shelltron may serve us better as a damage shield against physical damage for 20% of our hp.
The issue with it is timing. Unless the tank buster has a long cast time, or you know EXACTLY when it will hit, an autoattack could eat your forced block... Which just sucks.
If they are set on it being a blocking effect, make it a bit like Warrior's Raw Intuition, where you block all attacks from the front for 3 (maybe 6) seconds. That way the effect is more or less the same, but it will not be eaten by something weak if you use it early... Think Titan's MBs which are instant with an autoattack before and after.
