Would be nice to have a single thread on grenades, instead of a couple million.
If they are added, I think that they should mostly be used for sieges, with players being able to pick up grenades and fuses from a preset position (a barrel? a crate? idk) with a limited amount that regenerates over time. I don't know whether they should be used by defenders, attackers or both, however I think that this (and the time it takes for the grenades to regen) should be decided with balance in mind.
Maybe there could be different grenades for defenders and attackers, with attackers having more conventional and iconic spherical cast iron grenades that can be thrown relatively far and defenders having larger, more makeshift grenades that can be thrown much less further but have a larger explosion radius (I was thinking of those things in the walls of Martello Tower. I think they're thrown/dropped explosive devices of some sorts. Not really grenades, but you know what I mean. I'll probably take a picture when I get home. Think of the stuff used in Sharpe's Mission, if you've ever seen it.)
I don't know whether or not they should be used in naval battles. Perhaps they could be used by specialised sailor classes. Maybe they could be used in a similar manner to the system I described earlier. However, if this is the case, I think that they should be limited so that they don't indefinitely prevent other ships from boarding vessels that have grenades. Either way, I think that they should be used more, if not exclusively in smaller vessels as to balance things out a bit more between ships.
I also don't know how they should be lighted; whether officers in sieges and naval battles should carry fuses, whether the classes that carry grenades should also carry fuses, or whether grenades should function more like grenades in modern shooters, with them just being thrown and exploding after a certain amount of time or the player using the grenade pulling out a match or something to light it. Perhaps someone more imaginative (or someone with a greater knowledge of history) can think of this.
Hopefully Refleax or someone else sees this so it doesn't go to waste.
Edit: Perhaps sappers could place down places in which other players could equip grenades.