It isn't that the current grenades are lacking in lethality.
Rather, I'd offer that the vanilla game's specimens are generally able to minimize the grenade's apparent effect by scattering away. As a result, I would say at least some of the desire to buff the grenades is stemming from that. In a player's early stages in Beginner difficulty, where the specimen's hitpoints are trivial, and they may as well be on crutches in terms of movement, this zed characteristic is scarcely noticed. By the time a player graduates to Hard difficulty, where the specimens are more robust and their pace is markedly more quick, the perceived usefulness of the grenades seems to diminish. So, to offset this specimen behaviour, it follows that something with more punch, and/or a larger blast radius would be desirable; a perfectly understandable reaction.
The better alternatives would be to either adopt the "cooked" grenade mechanic of poosh's excellent ScrnBalance mutator into the game, or, simply end the specimen's grenade phobia. (Doing both wouldn't hurt. I think...)
I fully realize that some players have leveraged the game's zed grenade avoidance mechanic into an artful part of their personal repertoire, using grenades to momentarilly delay and misdirect the specimen's advance. However, I suppose I look upon grenades first and foremost as weapons. (You know, as in, "Die! Die! Die!") As they are now, their performance, as weapons, isn't what I would describe as being very reliable. True, if you use them within the relatively narrow confines of KF-BioticsLab, they're not all that bad. In a more roomy environment, or outdoors? Not so good. And, it isn't that the grenade is weak. It is because it is the only player weapon that the specimens seem to fear.
Consider: I guess the next-closest thing in the game to grenades would be pipebombs. If the specimens demonstrated the same behaviour towards pipes, (that is, avoidance), as they do towards grenades, there would be a ton of unexploded ordnance lying around on many maps. Not to mention, a number of routes of travel the zeds would steadfastly avoid. That would be a pretty boring game, no doubt.
Aside from the smoke issue, I'd always imagined that it would be good, (or, at least interesting), if a Demo could just grab a handgun or two, and, say, two dozen grenades. (If the perk permitted such a thing.) Simply forget the launchers, rockets and pipes, and work through several waves being, in essence, an old-skool grenadier. With the specimen's current "Bust a move everyone! Incoming frag!" behaviour, this probably wouldn't be a viable way for a Demo to earn a living.
