Glad to see this thread started, I've had some thoughts about the game since it was released I wanted to share...
I posted on the OT shortly after launch that I quickly got burned out on the open world. There were only so many bandits and Mongols I could fight before I got sick of the repetition of it all. And it very much had that Ubisoft outpost feeling of opening up the map. Every time I talked to someone there would be more and more sidequest waypoints added, which when finished would unlock more, and so on, and so on...
When I posted of my burnout, a lot of people said stick with it, that Act II was so much better. But I let it sit on my backlog for a couple of months before I returned to it. Things quickly happened in my second round of playing that enhanced my enjoyment of the game: 1) My understanding of the stance system and how to use it properly; and 2) unlocking the grappling hook, which added a new dimension to enemy encounters. And yes, that Act 1 ending was pretty awesome to experience, and made me want to push forward to further experience the story.
I'm a completionist, so these types of games really wear me down. If I see a marker on a map I feel like I have to clear it before I continue. I'm still struggling with this feeling in Act II, primarily because the world is so beautiful I don't want to miss something spectactular or enjoyable. And also, now that I have added some skills and understand how to switch stances based on enemy encounters, I'm pretty overpowered and combat is a lot of fun.
I also took another break, for no other reason than I was just busy with life, but I plan to pick it back up this weekend in hopes of completing the game by the end of the year. I'm about 27 hours into it, but haven't played any of the main quests in Act II yet.