Now it might be the salt of dying to two vog-25s tonight that's fuelling this but to me vog grenades feel broken and in my opinion shouldn't be in the game.
While I am glad they removed them from the scavs (because that was ridiculous) they don't feel in any way balanced, at least currently.
To me grenades are for clearing rooms/getting your enemy to move. You might be lucky and every now and again get a kill but mainly they're a tactical tool.
Vogs on the other hand, providing you are a good enough throw you are a guaranteed kill. By the time you are aware that the grenade has been thrown you are dead and to me that doesn't seem balanced. That means that even if you are a landmark you can get the shot and still die to the grenade afterwards.
As far as how to balance them a start would be the price/rarity. At their current going rate on the flea market of ~25k this seems incredibly cheap.
Just my thoughts so I am sure someone will disagree but please refrain from suggesting I start using them as well if I think they are so strong, do you want to live in a world where everyone runs vogs?