So I feel immensely late to the party here.
But god damn, the pop-in in AC Rogue and AC Unity is maddening.
Seen some people say you get used to it but, I dunno, it's pretty abundant.
Still been enjoying them, don't get me wrong, but only in a 'fucking about in the world' sense, struggling to get invested in the story when there's bugs that mess with quality of life, and such a vast amount of pop-in. This is on the highest graphics n everything too, my computer ought to be able to handle this stuff (I mean, it ran Watch Dogs 2 on highest smooth as anything with no pop-in or weird textures)
I hope it's better once I get to Syndicate, but then while I was rushing through Rogue I thought to myself "I hope things have improved by Unity" and now, err, apparently not. So my hopes aren't super high there.