They do need to go away. HMs are easily, and I say this with absolutely no exaggeration, the worst mechanic in Pokemon. They serve little purpose, and I say this because Pokemon's never been above shamelessly making boundaries just because. One instance in BW, in particularly, had a wall of NPCs guarding the entrance to an area for literally no reason at all. And they tell you specifically that they're there for no reason.
HMs not being mandatory was easily one of my favorite things about XY, and it made getting into ORAS after the fact very jarring. Having HM slaves again was not something I missed. But the whole idea behind HMs is that they either block the player off from specific areas until the time is right or to "entice" them to revisit areas after they get them. However, the problem comes with the fact that both of those are very frustrating. Can't say I remember a time where I had more fun getting lost in Dark Cave or smiled like an idiot when I ventured down a long route only to realize that I didn't have the staple of staples- Cut. And that's what's worse, a lot of the moves are either superfluous or just plain not very good (gen 4...defog...just y?). More, there are so many HMs that generally the player will have 1 or as many as 3 HM slaves, usually made up of the small amount of Pokemon that can learn multiple, limiting not only what movesets the player can use, but also pushing the player from making a varied party and choosing HM-versatile Pokemon like Pelipper, which really isn't a good idea for a game that now has 700+ monsters to collect. It detriments the entire concept of the game.
And I worry that the devs might consider this some sort of hallmark of the series that fans would feel is a major loss if they reworked or got rid of it in favor of something more interesting like, say, having certain Pokemon innately be able to use the functions of various moves (which makes sense for many reasons and would ultimately make individual Pokemon 3-dimensional, as if what Pokemon they are actually matters to the world at large) or something even more fundamental than that. Some people would be, but if a few huffs is what it takes to get rid of/rework a feature that is there literally only to frustrate people and limit what Pokemon they can choose, is that really such a loss?