Out of the choices that cirno gave I would probably prefer - "No stealth penalty ( no PE loss, no armor bypass )"
That along with a weight threshold bump, or the suit providing a bonus to stealth (like the 25 from a jacket) would be really nice IMO.
But Ramons idea of resneaking after killing is quite cool, if it worked like bloodthirst (must kill while stealthed to get the buff). But then we are talking about the potential for psychopath, bloodthirst, sprinter and an instant stealth buff on kill stacking together, which seems OP, seems anyway
Just to be different I really like the idea of being able to enter stealth while being looked at in the suit, that along with the "no stealth penalties" option would be really good (along with I assume decent armor provided by the suit).
Either that or no stealth penalty and insta sneak when you get a kill while stealthed.
Very powerful, but as ramon said, it is the sneaker/light equivalent to PA (in terms or tier, expense and rareness), so it should be good.
You could have a weaker and lower tier "camo suit" to accompany it, that works like the new camo kit and/or can be entered into stealth with no SEC drain (perma stealth, EMP kills temporarily). This one can keep the sneak debuffs (aside from -PE maybe?) and even have paperwall to balance it.