That's a complicated question. HMs were always bad as a concept: the things they are things that should be able to be done by Pokémon without prompting (like say, surfing, flying or Flash) or things that you could have easily gotten via a key item (think Clippers for Cut, Flashlight for Flash, etc.)
There was never a need to burden a Pokémon with them as moves and because they're moves they naturally introduced situations where you could softlock, making GF have to test and avoid softlocking.
Still, I think the worst it got was probably Gen IV, yes. To the point that GF themselves were already easing them out in the next gens (that's one of the reasons Gen V is so linear).
Still, the lack of HMs doesn't have to mean linearity. The Alola system works out fine, Key Items would also work as well and those are the "lazy" options. The Switch has the power to have dynamic levelling / look-up-tables so in theory there's no particular (game) reason you need linearity to have a steady game curve.
In the subject of roadblocks, a good roadblock should be something you as the player can see, understand why it's happening and think of how you can solve it.
So, for example, when you have people say "We're just dancing here for no reason!" (cough cough BW2) it's annoying because:
- there's no decent reason why you couldn't just squeeze through in-universe
- there's no obvious in-universe indicator of how to stop it
ShSw's Team Yell is actually a little bit better because the roadblocks there are dumb on purpose. Team Yell is coming up with dumb excuses to hinder your progress and make Marnie get a bigger lead. So it's dumb and annoying but it's meant to be dumb and annoying (at least I think so, maybe I'm being too generous with GF right now).
That said, it's not good because it's not something you as the PC could theoretically solve. If Marnie just got stumped by one of the gyms when you didn't, Team Yell could have very easily just said "lol nope. you're all staying here until Marnie gets through" and kept stalling - the only reason your gym win opened up the way was because of plot contrivance.
So it's not so much the lack of HMs that are making bad roadblocks, it's just that Game Freak is being even lazier than they needed to be with their game design c :