No. It isn't that much more powerful first of all. Second, we are in diminishing returns territory and any gains in power aren't going to translate directly into more detailed graphical performance in game. Third, PS4 will have much more going on in the background than the Wii U, so much of the extra RAM and compute power will be reserved for those tasks. Fourth, we don't exactly know the raw power potential of the Wii U, we can suppose things based on what we know about the GPU and CPU dies, but those numbers don't make any sense when we see trailers like X, which is a pre-alpha trailer that shows a massive amount of detail in an open world that would require more power than what many believe the Wii U to possess.
They will be graphically on par with each other. Later in the generation, When the hardware is fully understood on both consoles, developers will most likely be able to eke out better LOD or higher poly counts but they won't be visually discernable details from a gameplay perspective. The Wii U is much more powerful than both the PS3 and the Xbox 360, that much has already been shown. The ports that came with the launch were developed toward weaker target hardware and most developers received dev kits very late (last 6 months) because the hardware wasn't finalized until shortly before launched.
Everyone seems to be praising X, but to me it didn't seem that impressive. It looks good, but amazing? Nope. Yes I know it's in early stages but no, far from impressive. Killzone looks better than anything I've seen on Wii U to the moment, except for the Zelda demo but that was a demo in 2011, maybe hardware has changed and it can't run it anymore (which I fear, but it's not likely). The PS4 is obviously more powerful, but I don't think that's the Wii U's problem. The reason you want to buy a console is for its games anyway, and currently, there aren't many for the Wii U. But this will change after E3. I mean, hell, a new Smash Bros, 3D Mario and Mario Kart in glorious HD? I'm gonna have to work my ass off for that, but I NEED it.