Never really dug in to it mechanically but Gen 5 was a step back in terms of the single player adventure. Boring circuit region, cutting back on on HMs, just blah. Infinite TMs and the attempt at expanding the narrative were nice but the whole endeavour was a step back from D/P/Pt.
HMs are the worst things ever, they need to be completely removed and replaced with items, with the good moves turned in TMs. All it does is encorage HM slaves or force shitty type coverage and moves onto a players core team.
I know I am not a fan of water types carrying Surf, Waterfall, and Dive all at once.