So a stealth built Commander can sneak up to a group, kill one before the stealth points run out and noone else can see him? Then he can move on to the next one and as long as he neutralises enough of their reveal points, will remain stealthed?

It kind of makes sense from a sniper perspective but seems unbalanced in the stealther's favour. I think attacking should reveal you to everyone in LOS, this sounds like easy-mode right now.

Ya that does seem a bit overpowered. I don't see why the person being attacked can see the person in stealth but no one else can. I think the person in stealth should either become fully visible to everyone after having attacked someone, or not at all.

Except it falls within the guidelines of what has been in the show.  Invisible people in SG1 were generally invisible to all, even during attacks.  I don't necessarily agree with having stealth classes in an mmo anymore, however I can see why they are going to try from a "lore" standpoint.

If they keep stealth as it is, it will certainly make Stargate the laughing stock of the MMO's.  If that is not completely overpowered, I don't know what is.

Stealth should be walking in shadows ONLY.  It should never ever be complete invisibility.  Completely invisibility has caused major issues in games since the inception of UO.  You would think these developers would be intelligent enough to realize from past history that is just plain does not work without suffering major balancing issues.