Oh totally agreed on the diversion of resources, and even before the machine (skills hired, teams divisions etc).
However open worlds, imho, pose challenges but not to the extent that it explains or excuses the lack of 'basic' low-level (physiological almost) engagement. It's a different problem I think, e.g. consider the 'blandness' of a typical NES or early PC world, and yet how engaging some titles managed to be. That's what I'm talking about. Sure, visuals help immersion (so a great open world may help, a bland one may deter), but this is at another, higher level than controls.
For instance, even in 3D, I remember having more fun "farming" in old-school ugly MMOs — up to and including WoW 1.x — than in later very "rich" worlds. The problem is so basic: for instance, visual feedback not perfectly timed to provoke "satisfaction" or a "reward" feeling, but rather feels frustrating and/or working against me (the worst feeling ever in a game, when the part that's yours — e.g. feedback, hitpoints — seems rigged or not fair or simply deceitful / obfuscated).
I remember reading Square Enix devs for FFXIV that "yes, boss X is essentially 'cheating' but that's because hollywood experience! better this way!"... — err, no, sorry, not ever was a game better because your opponent is visibly unfair — hasn't anyone learned from Metal Gear. This was the day I knew I just couldn't keep playing the game, it would never be satisfying to me because of its design philosophy.
As a friend in game dev at Capcom explained to me once, player controls is a very tedious work of finding the "ideal" timing windows and key combinations / orders that just make it "fun", subjectively. It's a lot of back-and-forth between code and testing some alpha — hundreds of times over a typical day. It's almost biological in nature, like good music. And stupid loads of time + great tooling are paramount to do this job well — one reason PlayStation SDKs are so appreciated in the industry ever since day 1, 1994; a polar opposite to Nintendo's for instance (I hear they got better, but look no further to explain 'lack of third-party support' on many of their platforms).
Controls may be "precise" but above all need to be predictable, learnable — like Sonic has always been 'sloppy', unlike Mario, but this ties in well with his speed (hence inertia) and persona (go-getter), and it's a small learning curve for players, but one that sets 'experienced' players appart. A great "sloppy" implementation, nonetheless precise mathematically.
I definitely have to check out Hollow Knight, though!
Sorry for a long piece, it's one of my 'truths' in game 'quality'. Note that this is all good advice to design UI in general for any kind of software — especially the timing of action, feedback, effect on events. There's a way — through testing — to make it all just 'flow' 'naturally' and with a weirdly 'satisfying' feeling.