I think I've worked out how to fix the disconnect I have with grenades.
I'd like to make a suggestion.
The problem I have with grenades is that they look like official military grenades. They look like the explosive devices I'd expect to see when someone uses the word 'grenade'. However, the game has only minor damage for them (versus the result I'd expect to see if I threw a proper grenade into a cluster of gangers).
My suggestion:
The current graphics are great. On the assumption that there will be more powerful grenades, the current graphics should be used for those.
For the current minor-damage Mark 1 grenades we have now, change the graphics.
By the way, I understand that the damage is less due to the ability to hit multiple targets, but the current explosives DO say Mark 1, implying that there are more powerful ones. =)
For the fire grenade, make it a bottle with a rag.
For the explosive grenade, make it look like a home-made I.E.D. (could even just be a fat plastic bottle (bleach?) with some wires).
This, to me, would explain the relatively minor damage inflicted.
Then, when (or if) we get Mark 3 grenades later, these are the military-looking grenades we see now.