The ALIG is meant to be AV. It fills that role in a team squad. IMO it should not ALSO be viable as AP as well.
SHAW is a cqc beast, better than both SMGs and shotguns. Asking for it to be just as good outside of that range makes about as much sens to me as asking for shotguns or SMGs to do the same. Its already better than them at range, so IMO its fine.
Medusa already has an insanely fast ttk (.59), PLUS it has a 70m dropoff that thanks to its unique mod it is actually useful at. Absolutely no reason to make this better.
From my perspective, the only LMG that maybe be a little too strong (especially with HB2) is the N-SSW. But again, this is not a gun you see in high level gameplay, so Im not too concerned about it anyways.