My suggestion would be to implement HMGs as similar to tanks.
- 2 crew for simplicity's sake - gunner and loader.
- Gunner carries the gun (duh)
- Loader carries the tripod and spare ammo
- Gunner is always a human; loader can be human or bot
- As with tanks, the gunner can 'lock' the position so no human players can serve as the loader, in case of idiots.
- Bot loaders are programmed to always stay within 2-3m of the gunner at all times.
- Gunner can press F to bring up that yellow arrow thing to tell the loader where to deploy the tripod.
- Loader deploys the tripod, then gunner deploys the HMG on the tripod
- (Loader could possibly carry a bolt-action rifle or maybe PPSh to help defend the gun crew while on the move, and to defend the gunner from the rear while deployed. Anyone know what would be historically accurate?)
- Loader possibly equipped with binocs for spotting for indirect fire? (Human loaders only of course)
- If the loader is killed, the gunner can still undeploy the gun from the tripod, allowing another player to pick up the tripod and become the loader.
- If noone replaces the loader, the gunner can still use the HMG by resting it on a stable surface such as a sandbag or windowsill, however with greatly reduced effectiveness.
- If the gunner is killed, the loader (not bots) or another player can take over the gun.
I actually like this idea a lot, but I would change two things.
The player carries the tripod, and when he deploys it the bot/loader mounts the gun on it. That way the gun will end up where the player wants and not where the bot is standing and/or facing. (I realize this is a problem since the player could fire the german gun while moving)
Second if the loader dies he will respawn in the next round unless replaced by a human first (not sure how that would work).
There are some fundamental differences though between the german HMG (which is the same gun as the LMG but mounted on a tripod, and the russian water cooled guns. The german gun could be converted back to an LMG by just unmounting it and replacing the bipod, or hip shooting it while on the move. The russian gun cannot be fired from a bipod or hip fired so there is a big disadvantage. On the other hand overheating is not a problem with the water cooled jacket.
On another note though I have been playing a lot as a LMG gunner and the maps don't really allow them to be used properly. They should have a practical range of 500-750 meter but I dont think any of the current maps have anywhere near that kind of space. I also don't think you can even see that far in game.