No if the PS4 would be like Wii U in terms of power why would anyone buy it ? What would be the benefit of having a PS4 compared to having a PS3 ? It would look nearly identical the machine would be slightly stronger. The games for it could be made on PS3 also and would be identical. Why would anyone ever buy a PS4 with the Power of a PS3 ???? What would change the plastic shell ? The Controller ?

If it was a powerful as the WiiU launching in 2013 without a gamepad, it would be $199. Cheaper then the ps3 slim, re-engineerd with off the shelf parts, updated GPU, 2gb unified RAM.
Keep the games in 720p and they'll still look better then ps3 games, plus 3rd party would optimize for wiiU+ps4.

It will start off fine, then get eclipsed by Steam box.

well if they launch the PS4 at a cheaper price than the PS3 maybe yes. But there must be somekind of hook price is not everything as the 99 GameCube showed. There must be a wow factor to the product or nobody cares.  

Depends if the X1 still would be as strong. If so I don't see much of a chance for the PS4.

If the X1 and PS4 were as weak as WiiU and WiiU as strong as PS4 I would still see PS4 winning.

Why? Because X1 and PS4 are not competing against WiiU but each other.