Agree with the weight penalties.
Concerning grenades, well, I bet PvP whinners will disagree, but I think it should cost 1 more Action Point, cause when you throw a grenade (I mean in real life), it doesn't explode immediatly, if you want to lower the delay, you have to wait before throwing it. Furthermore a gunshot is faster than a grenade throwing (except aiming shot, of course).
Let's start the complaints... 
so you want make grenades unusable for PVP, usable just for PKing in mines.
This is game not real life so dont think about how it works in RL, in real life you cant get shot to eye and then heal that eye with doctor skill too...
Now throwing is usable, you dont deal big dmg to enemies but you can stun them , so its good for team pvp, and sneak with that can be good and i think that grenader with sneak ,(if will be sneak reworked) will not be overpowered. it will be just next usable character for pvp .
Grenader without sneak will be shit,(he cant fight agaist bigguners because of diference between dmgs, and he cant fight agaist snipers because of diferences in shooting range.
And grenader without sneak and with throwing for 3AP (or4) will be double shit.
but this is topic about sneak , and problem isnt just in grenaders , problem is that they use miniguns and CAs in sneak.
Can someone just tell if it is possible or impossible to add penalties (weight,armor,weapon).And if is , is time for do it, because pvp is now unplayable.