At least Horizon has so much more going for it that it that it can carry that formula somewhat. I do remember hearing that the developers for that game, in the promotion period lead-up to release, liked to talk a big game about how their open world missions were less predictable, artificial, and repetitive--and then I played it and couldn't help but think "Are you kidding me? This is exactly the same kind of artificial filler, paint-by-numbers quest / task log that you claimed you were trying to avoid..." But that sentiment was hidden under heaps of "Ohhhh yeah, f*** you giant robot stormbird that one shot me last time I came through here. I got binding cables, blast arrows and an electric bolt thrower now, and its time for a reckoning!"
Seriously, it's such a well developed and polished game in terms of gameplay (particularly combat mechanics), presentation, and even one of the very, very few genuinely well-composed sci-fi stories in the genre--as regards the main narrative, anyway, and less-so the fetch quest stuff, as per the above--that I was more than happy to fill the skill tree and wander the map using those random tasks as an excuse to engage with more robot fauna foes. it was the first open world game that I had played in some years and probably the first in a decade and a half that I played with an outright completionist bent: I scoured every inch of that map and did every subquest, bonus area, trial, item search, collection task, and skill or equipment grinding milestone the game had to offer--and then wasted a bunch of time just honing my methodologies--before I even finished the second half of the main quest line. And enjoyed pretty much every minute of it.
And yes, despite all of that praise, it still was very formulaic in the way its world and activities were designed. But it also brought in a lot of features from other genres and synthesized them in a compelling and polished fashion, had some of its own unique innovations on top of that, and, most importantly, was just enjoyable on its own terms. I think, without disagreeing with you in the least that H:ZD is significantly of the Ubisoft-derived model we are criticizing here, its also an illustrative example of how that's not always a problem in itself when the activities you are being asked to repeat feature depth and variety in how you can approach them, merely by virtue of breadth of the tools you are given and the fact that the experience is firing on all cylinders on a technical level.
The problems arise when a game doesn't present enough novelty, polish, and in-the-moment enjoyment (as opposed to "gotta do it all" OCD motivations). When it's just, as styus framed it, pure padding for an experience that really can't carry the investment on experiential merits, but just taps into a the needs of a certain type of player looking for that artifical, arbitrary task-reward response and checklist obession. I rarely felt that way playing Horizon though, right up until the point I exhausted things to do. But I admit that it's extremely rare that I feel that way about a massive open world game: Red Dead Redemption is maybe the last such game where I was just having too much fun playing it too much care that many of the tasks boiled down to the same seven or eight activities, over and over.
