I'd go with an 8/9 for this. Endgame is utter trash and the dark zone needs a significant rework, but the base is really solid. Having played a ton at this point, it's amazing how it feels like some of the game wasn't tested at all. Things like the insane rogue penalties in the dark zone shouldn't have made it past internal testing. If you join some friends as a higher level, everything will jump up to your level and make the game unplayable for them which is obviously idiotic. How did no one notice this during testing?
Even though I'm pretty positive toward the game overall, I think it finally broke any hopes I had of this genre being what I want out of it. It's just too hard to get right. Ubi dropped the ball with the garbage talents, terrible endgame, bland mission designs, ineffective matchmaking, etc. They had a ton of time since Destiny launched and still wound up repeating a lot of vanilla Destiny's mistakes. I'm unsure how it's 2016 and devs still have no better idea for creating challenging gameplay than just ramping enemy damage and health up to 11.