Unlettered 81s would be better than lettered 82s, yes. Whenever the new HM drops it will have better gear than NiM..just like HM DF and DP are better than NiM TfB/S&V. They basically make the NiM pointless as far as gearing goes. And you can buy better gear than the NiMs currently with comms as well. If you can buy the same tier as NiM with comms but only lettered then comms would buy gear behind what you could get in NiM and HM...the way it should be IMO.
Do NiM for related gear when it is current or don't. This 'no child left behind' mentality is destructive and will never happen. Put yourself in a position to do the content for the BiS gear like everyone else who runs it has instead of devoting the time posting about refurbishing loot tiers to accommodate your lack of progress in the game.