I don't think Stalkers are overpowered, just the ability Assassin Strike. Of course there are ways to protect myself from it, the point is that no hero or villain should be given the ability to kill with one hit in the first place.
Unfortunatley, since it seems to be the only efficient pvp power early on in the powerset, it's the only one used. That seems unfair and unbalanced for both the stalker and their prey. can't we tweak the numbers a bit, tone it down a little and bring the other attacks up in damage a little?
All too often I find myself lying dead on the ground of Siren's Call simply because i stopped moving for a moment. I can't always be in motion, and I can't always have defensive buffs from other players, and I honestly don't mind being soundly defeated in pvp, I just find it impossible to enjoy myself when every moment spent in a pvp zone has to be focused on avoiding only 1 skill from 1 archetype.
The biggest problem with this issue is that the ability to kill with 1 strike is, of course, going to be EXTREMELY popular, and true to form, I am hit with an AS like clockwork, once every 2 minutes on average. This proves to me that Stalker with AS is the "best" build, and there can never be a "best" build in a multiplayer game where balance is absolutely essential.
As somebody who takes pleasure in being defeated by cunning and ability, and who looks forward to revenge, the complete and total lack of joy and desire for revenge after an assassin strike tells me that this power still needs a bit of tweaking, and maybe the rest of the Stalker set needs a bit of a powerup. I would love to see what other skills Stalkers possess, but they only ever use 1 skill on me, and that's sad, sad for them, sad for me, and sad for the entire pvp experience...