Honestly? Good riddance, I've never been comfortable with the HM system and I hate how it felt so restrictive in the earlier titles. Sure some moves are great like Surf but who wants to shackle a Pokemon with Flash? Especially when it's mostly used for one or two dungeons. Not to mention it can be annoying having to reshuffle your party because the next area requires an HM skill, so just having a rental service sounds like such a better idea.