HZD will stick in my mind for a long time and that's as much to do with its story (specifically the one about how the world got to be the way it is) as anything else.
Finished this last night and unfortunately it got a bit disjointed and dragged on a little. From the point of no return to the ending, there were many a moment which could have been cut and the time allocated to help make the best mission (as regards to drama if not gameplay) that much more impactful and unrushed. Oh and if Origins had been subtle about the whole Assassins thing for the majority of the time then it went stupidly heavy-handed toward the end
One scene in particular actually made me laugh/cringe out loud, but it was also clever in a wee inconsequential way.
The open world is as good as any I've explored (to say nothing of how stupefyingly gorgeous it is in places - the only game to make me wish I had a Pro, etc) and the core AC gameplay was so good that it actually not only unseated Black Flag as my favourite AC but made me reconsider its place in my all time favourite AC list in general
But I think I'll have to revisit BF and ACII to make certain of that. Oh and if I wasn't renting it I'd still be playing it.
edit: Actually, DB FighterZ is still quite a way away and I left many a place unexplored in AC:O...