see, the thing about this is stalkers get like 39% defense to AoEs in their hide while unsurpressed. it goes away as soon as they attack, but it pretty much gives every aura a negligible chance to actually uncover one, since the base ToHit level in PVP is only 50%.
Yeah but most of em will interrupt an AS automatically.
Very good point. Probably more important than knocking a stalker out of their hide, is interrupting their assasin strike.
Well I have a stalker and I get interrupted every time I try to AS when someone is running an aura. I have def powers on which give me 20% def plus hide and stealth. The only way I can kill AS them is if I use some purps so their aura doesn't hit me.
Purps wont help against auras with auto-hit slows. They'll interrupt AS every time.
A good Stalker has other ways of taking someone out other than AStrike. It is just the easiest due to it's huge damage.
I'll give you a nice tactic (one of many) that I have come up with so that you can start to work a defense, (a hint from your Uncle Czar 
). I'll TP Foe someone to me. The hit ET and placate. Usually this stuns and drop toggles. Now I can AStrike. 
While it is not 100% effective (maybe 30%), it's more effective than just AStrike and scrap like most Stalker try.
Total Focus, however, is a lot more reliable since it'll auto-disorient anything that doesn't have mez protection, and has a pretty damn good chance on the ones that do. It just has a long activation time and a bit less damage than ET, but you're not really using it for damage in this case, anyway.
Frist off let me start by saying I went to warburg with my brute and my SG mates keep getting AS'ed so I made a stalker to find the tricks and here they are.
One of the best things u can do to stalker-proof is to have an aura running or be with someone that has one running. Here are of some of the auras. Repel, lighting field, blazing aura, death shroud, mud pots, repulsion field, hurricane, hot feet, artic air, chilling embrace and quills. Now this won't make u completly safe because only a couple of this are autohit chilling embrace being one. To help with this you could slot some of these with acc. These auras should keep the majority of the stalkers at bay however if the stalker is smart he could just pop some purple pills AS you then be on his way and some of these that just knockback or lower acc can still let a stalker through if he pops enough yellow or breakfrees.
Hope you enjoy