Graphics Comparrison- PS4-PS3-360-Wii U for AC4
IGN put out a graphics comparison of AC4 for Wii U, PS3, PS4, and 360
In general PS4 is claimed to have better graphics power than Xbone so not having that in there isn't a big deal.
Sure PS4 graphics will likely get better over the consoles life cycle and it does have the best graphics in this comparison but I do not think it is that significant.
I have been hearing that this console generation does not really have that wow factor to the level we have been used to seeing. Ps2 to PS3 was a huge difference going to HD for the first time, but seriously I would be hard pressed to watch some of these and pick out the difference. I don't think just looking at some game footage it will be as immediately obvious what is PS3 and what is PS4.
What I am thinking is that while the Wii was significantly behind the HD twins last console generation it doesn't seem to be the case based on what I have seen so far. The Wii U will not be as far behind the competition graphically as it was the previous generation in my opinion. Whether or not that is going to matter much is another question. It may make these new consoles be adopted slower than many are predicting. With out that wow factor right now a large portion of consumers may wonder what is the point in upgrading to an expensive non-backward compatible console that has no games.