So the stealth mode is decent but not as much a part of the game or as critical to success as it is in Assassin's Creed since the stand-off feature kind of negates the need for it. I haven't come across a situation where stealth is critical to finishing the mission unless it specifically tells you that you can't be seen or caught.
The gear aspect in GoT is one of the best features compared to AC, in my opinion. I completely lost interest in Odyssey and The Divisions 1 and 2 because I felt as I got later in the game I was spending less and less time on playing the game and more and more time deconstructing or selling excess gear and messing around with the builds so Ubisoft games lose my interest after a certain point.
The side missions are much better in Ghost of Tsushima as well, I think. The story seems to fit better and what you get out of them is more useful to the main story. Do as many as you can so you can kill as many leaders as possible and learn different stances which is a really cool feature that I think players of AC may overlook.
I'm into it for about 6-7 hours I think at this point and really enjoying it so far. I think I'll finish this then go Cyberpunk 2077 and then pick up AC: Valhalla once it's on sale.
One of the most annoying aspects of AC is the side quests are totally optional, irrelevant, and unrewarding.* It feels like busy work for compulsive people that's tacked on to extend gameplay, and once the novelty of the setting/theme wears off the side quest process is definitely a chore, especially since most main quests can be won with a few key, common moves or items.
So I abandoned any completist obsessiveness for ACO and finished the main story, "solved" the riddle of the Sphinx, and downloaded GoT.
Another thing that I think I grow dependent on in AC games is the ability to "scan" the area for interactive items. Going back to a game where you have to actually pay attention to the environment in every detail will be more interesting.
I'm hoping G0T also makes the little things you find/read more relevant rather than historical footnotes or filler, as with AC. Do I *really* need to read this wall of text I just found about some bizarre alligator ritual, or is it a waste of time? In AC games it's usually a waste of time.
*edit: there was one tomb/puzzle I found that had some powerful and unique gear/mount as a prize but that was all I saw after uncovering the whole map and probably hitting 90% of the question marks.