Dang Pikachu, all this fame has gone to its head! Then again, being the mascot for one of the biggest franchises in gaming can do that.
HMs were easily one of the most annoying aspects of the Pokemon series, even in Gen 1 when it was first introduced (I can only imagine how many players taught "Cut" to their starter and ended up regretting it for the rest of the game). Getting rid of them is just a massive improvement to the overall game experience. Honestly...I'd buy Sun & Moon for just this change alone.