LMG and Weapons Platoons

[Imp]

If the LMG groups have nearly the same role as an MMG or HMG unit has there been any thought to giving them the MG icon or perhaps a similar type of new icon?

They don't they have a similar role to a squad. They have similar range so need to be at the front rather than towards the rear. They take fire similar to a squad as in for a group with 3LMGs which is what I think you are referring to they are reasonably spread out. 3 groups & say a commander. So probably 30-60% of the men are watching the flanks etc.
MMG & HMG are grouped round the MG so are crewed weapons & far more susceptible to taking damage if a hit occurs because of it.
The crew icon reminds you that unit taking fire can hurt.

Never seen one with anything above a 60mm mortar