Honestly its the smokescale, not GS, with LB stealth on top. Stealth from GS3 in smoke bomb, evades on smoke assault, GS4 block, LB stealth, just the dodges you have with energy sigil, maybe lightning reflexes and there you go, you have a pretty good evasive sequence to not get hit much.
Remove the smokescale and things look differently. At least they removed the knockdown on takedown...
Ranger GS is a strong weapon, yeah, but its not broken on its own.
GS2 you can get behind the ranger to avoid the dmg and that is the dmg of GS, nothing else on GS does actual dmg. Though of course you are usually eating GS2, GS5, GS2 while being CCed.