The Wii U GPU is only based on a R700 but is tweaked in many ways. With the Wii Us tesselation unit DX11/OpenGL3 should be no problem since tesselation is the new main feature of DX11.

The only official plattform for UE4-Engine is the PC. Epic had begged by Nintendo, MS and Sony for high-tech, so that UE4 makes sense on these console, but it seems that wether Wii U, or Xbox8 or PS4 has the power you need for full UE4. But UE4 is scaleable so in the end every gaming system gets its version, and there will be not much difference between Wii U and XBox8/PS4.

Didn't the Tekken developers say the Wii U was under clocked. I don't know how that affects the performance of the system, but I figured I would throw it out there anyway. I've come up with a theory about the lack of killer app 1st party games for the Wii U. I think Nintendo is afraid to put too much out in the open because for third party developers it would seem like business as usual for Nintendo. I think it will be at least 6 months before we start to hear about Zelda, Metroid, and 3d Mario games. This will give 3rd party companies a buffer zone before their games become over shadowed by what we are all really waiting for. IMHO.

The tesselation unit in the R700 GPU is basically the same as the one in the X360's Xenos and is lacking several features that DX11 hardware tesselation uses, and tesselation is just one aspect the other is more advanced shaders that offer much more flexibility, and native BC6H and BC7 texture formats (compressed textures can be processed natively with no performance hit by the GPU hardware so they take up less RAM).

UE4 is scalable but seems to require a DX11 GPU and to port it to a system with an older GPU will require the renderer to basically be rewritten.

http://www.geforce.com/whats-new/articles/stunning-videos-show-unreal-engine-4s-next-gen-gtx-680-powered-real-time-graphics/

Tim Sweeney: "Unreal Engine 4’s next-generation renderer targets DirectX 11 GPU’s and really starts to become interesting on hardware with 1+ TFLOPS of graphics performance, where it delivers some truly unprecedented capabilities." 

hence I am guessing the reason why Epic have decided not to support Wii U (or any current platform that doesn't have a DX11 spec GPU) with UE4, and are instead pushing UE3 for the platform. With Nvidia Tegra 4 and PowerVR Series 6 GPU even smart phones and tablets will have DX11 feature set GPUs later this year, even if they wont have the raw power for all the bells and whistles.

We don't know on which GPU the Wii U GPU is based and we don't know how this GPU is tweaked. The R700 is only an rumor. But the rough technical data we know looks more like DX11/OpenGL3 than DX10.1/OpenGL2.1. And we know that Nintendo tweaked CPU and GPU in many ways.

The tesselation unit in the basic R700 is not as flexible as in actual high-tech GPUs but far above the one in the Xbox360 that is based on an trimmed down R500.

it's faster but the V2 tessellator which added DX11 support wasn't added until the R800 architecture as far as I know. 

all those features on that sheet are basicaly the same as any R700 GPU http://www.amd.com/us/products/desktop/graphics/ati-radeon-hd-4000/hd-4350/Pages/ati-radeon-hd-4300-specifications.aspx

HD 4600 Series GPU Specifications 

Unified Superscalar Shader Architecture

Multi-sample anti-aliasing (2, 4, or 8 samples per pixel)

128-bit floating point HDR texture filtering

High resolution texture support (up to 8192 x 8192)

Indexed cube map arrays

8 render targets (MRTs) with anti-aliasing support

Independent blend modes per render target

Pixel coverage sample masking

Double-sided hierarchical Z/stencil buffer

Early Z test and Fast Z Clear

Lossless Z & stencil compression (up to 128:1)

2x/4x/8x/16x high quality adaptive anisotropic filtering modes (up to 128 taps per pixel)

sRGB filtering (gamma/degamma)

Programmable tessellation unit

Stream processing (an early GPGPU (AKA Compute Shader) solution doesn't technically meet DX11 spec but can basically do the same thing)

VS

Wii U GPU

Unified shader architecture executes vertex, geometry, and pixel shaders

Multi-sample anti-aliasing (2, 4, or 8 samples per pixel)

Read from multi-sample surfaces in the shader

128-bit floating point HDR texture filtering

High resolution texture support (up to 8192 x 8192)

Indexed cube map arrays

8 render targets

Independent blend modes per render target

Pixel coverage sample masking

Hierarchical Z/stencil buffer

Early Z test and Fast Z Clear

Lossless Z & stencil compression

2x/4x/8x/16x high quality adaptive anisotropic filtering modes

sRGB filtering (gamma/degamma)

Tessellation unit

Stream out support

Compute shader support

Up looks about the same to me, seems like any modifications are minor (other than the 32MB high-bandwidth eDRAM) and suggests nothing towards it being DX11 

He said that the CPU was slower, but since we don't know how they ported the game to WiiU (did they port the code from Xbox360/PS3 without optimization or did they tweak it to use WiiU's capabikities?) it's unclear if it will become a bottleneck or not.

After all, modern CPUs do a lot more than old CPUs at lower speeds.

Since when has 5th Cell been qualified to compare the PS3 or 360's hardware to anything else (they haven't developed anything for either system). This is akin to me publishing an article about the Higgs Boson. That being said, I have little doubt that the WiiU is a more capable piece of hardware than both the PS3 and 360. It would be difficult to believe that any aspect of the WiiU's hardware would be inferior to the current generation systems.

LOL about the buffer. Nintendo tried that with the Wii as devs said our games cannot compete with Nintendo's. Look hwere that got them. Huge long dry spellls.

I think this time around Nintendo will develop the games and have them on standby ready to deploy to retail when a drought is happening, instead of developing during it in the hope 3rd parties would release games.

It doesnt matter. The gen is over in a year. They will be far behind....in a years time.

No, they said its clock was "kinda low" not underclocked. Those are two different things.

They spoke nothing about its technical difference and overal capability of the processor.

NIntendo has already announced a bunch of first party games. Zelda and Metroid games are rare releases from Nintendo. You may see one every 2-4 years. Nintendo has never made a killer app for one of there own systems, ever.

NIntendo is not giving any form of buffer zone either. They will release what they have to release when its ready. If a dev can't compete with the quality of their first party games then they honestly don't need to be releasing on the system.