Hardware doesn't change. The PS4 will always be more powerful because the hardware is more powerful by default.
The 10% GPU, and DX12 will help developers get more power out of the X1's hardware, but at the end of the day, it doesn't make the X1 a more powerfull machiene, it just alwas Devs to use the power in the X1 more efficiently.
Take this for example. Pretend you have two race cars. One can go 200mph(PS4), the other can only go 150mps(XB1). If you put a better driver in the car (DX12/10% GPU) that can only go 150mph, it won't make it faster than the 200mph car, it will simply allow the 150mph car to be used more efficiently.
As far as the cloud, we honestly don't know how much of a difference it will make in games by the end of this generation (it could make a big difference), but for now, developers seem to be utilizing it primarly for AI, as well as physics, so it's not going to make games look any better anytime soon.
