There's a VR_ GLA user (I can't remember his nick though) I was literally unable to fight with my shielder. Shield down in 2 or 3 hits, then weapon stunned. Sometimes he even managed to glitch on the sides and hit through my shield or my block.
Why would you not put the shield on your back when fighting a GLA...?
Anyway:
If weapon stun is the issue then that has really nothing to do with this? To *counter* weaponstun what you need to do is to be patient and learn to see the animation when it happens. It's a questionable mechanic I agree, but it does not make fighting as a 1h impossible in any way.
Also: Regarding this "hit through block" business that people always seem to fall back on whenever they lose (no offence): I have ~65 ping usually and am on a fairly crappy line thanks to the town I live in and I VERY rarely see stuff like that. 99% of the time it's just animation glitches anyway and can be circumvented by trusting your gut more than your on-screen character.