I like the idea of GoD, it seems fun. What ruins it for me is that movement and damage are based on the seconds remaining. It makes it feel bad, to be super fast, then slowly slow down and deal less damage as you spin.
In my opinion, having a fixed bonus if momentum is active would be better than having a bonus per second remaining.
A secondary issue is that the primary skills shot out should count for any items that are triggered based on primary skills. I know other threads have mentioned this too.