I had no problems with that either. But I think it would be a dumb marketing choice considering what the changes from 3e to 4e meant for the game.If I were playing 6e and wanted something from 5e, I would just convert it. Same as I've done with scores of game elements from pre-5e editions for 5e. Most of the time its not even that hard. But it's my choice, and there would be a clear line for those like me who prefer that line to be there.