Maybe it is not overpowered. Maybe it's a different problem, one of playstyle. In my opinion, it is unfair that a single unit dictates how to play with and against a faction, which is what 1v1s come down to. That is supposed to be a support gun, and instead we have the entire faction supporting the LeIGs which pick a chunk of the map to "support", i.e. cause consistent, reliable manpower bleed and pins every several seconds.
Ostheer revolves around the MG42 support, and it is executed masterfully in-game. There is so much you can do to counterplay an MG42 (smoke and flank, anyone?

Imba or not, LeIG is still a crutch that prevents the rest of the faction from being evaluated fairly and maybe even buffed, it's the same issue with Rifle Company. Remove Rifle Company for two weeks and you would see 1v1 win rate for USF plummet.