I am nearly at 10 hours and i'm still on chapter 1. Reasons:
- The graphics are gorgeous at 1920x1080 ultra settings (no uber-spampling). Sometimes i find myself just looking around losing time apreciating the scenery, looking at what people are doing, exploring most corners.
- The journal is full of lore and writen from a storyteller POV, i find myself going a lot of times there and just read it.
- The crafting system, if you like it, its a time-sink for decisions
- I don't play on easy combat. I alternate between hard and normal.
- I do all sidequests and i normaly only go towards the "main quest" after i'm nearly done with everything else.
There is no way i'll get less than 70-80 hours out of this game if i continue like this, and i'm glad for it

its awesome.