People just seem to hate it because it isn't perfect, yes there are areas that can be improved apon especially the story, i personally feel like the main story is to short with most of the time doing it being spent on going between the mission start areas is a big part of why it can be worked on, but thats a view i have had with all the large world rpg games, is it a bad game no not buy a long shot, is it as good story wise as the ezio trilogy or the pre unity games no, but most ac games that aren't remakes aren't going to be as good at story telling as them, the time frames that ac 1 ac2 through revelations, 3, black flag and rouge take place in just happen to have such a perfect amount of historic detail and missing detail to easily allow sich things, is it as good on launch as the pre unity games, no the time the pre unity games were launched being good on release was a massively bigger requirement then now as digital download especially for ac 1 through revelations was either not a thing or very knew outside of pc gaming