When using the "Stone" handgrenade you can actually see that the projectile is a grenade, after hitting the ground there's an explosion sound being played.
It shouldn't be too much effort to bring back the old stones from Arma2, they dont't even need to get the possibility to mount attachments on them. ;)
Go to the virtual arsenal, equip some stone hand grenades and watch.
Proper stoning of incooperative subordinate units would be more fun with actual stones.
+1. I miss in Arma 2 when I was playing Takistan Life, holding a violent protest, throwing stones at the police. Although, you could also kill someone with two stones, so maybe damage could be toned down a bit.