Aromatic Mist
Sensuble
Another possible alternative is that certain HMs can do multiple things (Ex. Surf can also be used as Dive, Flyand Waterfall)
To be honest, I like how HMs work. Before I get mobbed, I'm more talking about the optional usage aspect, like how Gens V and VI handle it. Rather than just blasting through the whole game with one team, it inspires you to return to an area because you don't have an accessible HM user on hand, and may even get you to use that HM Pokemon a bit to expand your horizons.
Also, Strength, Fly, Waterfall and Surf, the most consistent HMs, are all decent, wide distributed moves. I think they should reduce the others to TMs like Rock Smash and Flash. I mean Cut especially, it's pretty much just Rock Smash for trees nowadays.