That sounds like a good idea at first glance, but in an older thread it was brought up in, someone pointed out that the auto reload function could be manipulated by your opponent.
An example could be to drive a light vehicle past the MG making it fire a burst at it then driving off to go do something else. The vehicle has now caused the MG to use up some of its ammo prompting it to reload after it is no longer in combat for a certain amount of time, for example let’s say it’s 10 seconds. Now our savvy opponent lies in wait and counts to 11 seconds and charges the MG that he knows is reloading. With this tactic an LMG blob could easily decrew an MG team that is busy reloading.
Part of me wonders if this could actually work via making units out-of-combat, in addition to having an automatic action to reload, also gain a modifier which makes their reload speed instant.
...but I am no modder, so I must confess that's only conjecture. I'm also imagining this concept would allow HMGs to be reloaded automatically without being set-up, and I can't even say if that's possible at all either.