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.
But then the comm bought offhands would be better than drops in NiM. So would the armorings minus set bonus.
Too much work would be involved to make this succeed. There would have to be a LOT of vanity items in NiM to make them worth doing more than once.