[Imp]

You make no allowances for real life in your ROF assumptions using the Greyhound example you give & it getting 35 shots a turn.

That means all ammo expended in less than 2 turns if it was possible.

It does not take into account several things such as & sure there are more factors
Time lost acquiring & engaging each new target.
Crew conditions often cramped could possibly manage something close for a short burst say 20 seconds top.
Switching from ready to stored ammo its not all easy to access.
Guns also overheat & have a recoil limit you cannot maintain a high ROF even if it was possible to do so.

About the only guns that could maintain a high ROF would be artillery pieces as the crew is not working in a confined space & can be supplemented more people bringing ammo & discarding casings.
This would obviously destroy the gun in the process so only used in dire circumstances so its not the norm.

Firefights are not continuous you might get 10-15 seconds of rapid fire in a heated engagement from time to time but its not the norm.
So taking things into account the ROF is not off by anything like what you say.

I would in fact say units die quicker in the game than real life on average so shortening the game turn makes it less realistic.
I may be wrong not researched but if you want more realistic I would say slight increase in rate of fire but with reduced accuracy so it takes more shots & time to kill things.
Infantry battles would drag it is a game after all so I am fine with it speeding up the action slightly as it still captures the feel of combat.

In simple terms compare using a weapon to driving a car how often do you put the pedal to the floor & how long do you keep it there? Weapons are similar you push them occasionally & normally for short bursts.