if you are close enough to hit him directly with a grenade... you shouldn't be using a grenade
same if you can see him. you should be using them to clear houses and kill concealed enemies.
seems like a pretty minor issue to me

Sometimes grenade is better to take down multiple enemies at once, even at close ranges, only thing you need to have is a good cover while throwing nade.

Nades can also ghost trough windows without breaking the glass.

The worst thing is that i cannot use a stone.
Stone ghosting trough a guy????? WHAT THE F*** DEVELOPERS THINKING? They thinking that stone can injury everyone by ghosting trough them like darter UAV do??? :D

to be honest, I don't even know what the point of the "stone" is... it just looks like a grenade, and it explodes like one, except without any explosion effect. The sound is still there though...

Yes, at the moment its quite strange. After about 5 secounds stone disapears and you can hear explosion effect and yes, it do not provide any damage even if you standing on it.

I noticed that nades can ghost trough windows.

Ok, maybe grenades ghosting trough soldiers are not a big problem but grenades ghosting trough a window may be a major issue while throwing nades trough windows (very common tactics in CQB).

Now its working this way: Nade is simply ghosting trough window without breaking glass and glass do not affects grenade's velocity.

It should work this way: If grenade is thrown from close range nade is breaking glass, going inside building and loosing some velocity.

Or this way when grenade is thrown from longer range: Grenade slightly damaging glass and simply bumping then injuring or killing soldier who thrown it :-).