The Wii U couldn't use any of the nice added graphical effects of UE4 so it'd be a waste of time. New engine doesn;t automatically and magically make the graphics better.

Source?

I'm sure it's going to have plenty of polish before it gets released next year. I wouldn't worry too much about it.

Meh, it is probably too late in the development life to switch engines, although if Nintendo and Valhalla had hooked up earlier in the development cycle this might not be the case. Sadly the pairing probably happened within the last 12 months when Valhalla realized there would be no potential audience for the game on the outdated 360 or PS3 by the time they finished and they didn't have the funds to try to convert it to the PS4 or X1.

Honestly for this game sake, I hope the multiplayer is off the chain because with Bayonetta 2 hitting stores first, having more appeal in terms of characters, graphics and brand recognition, Devil's Third has a rougher road ahead of it then most if not all the other games Nintendo showed off at E3.

Actually since it is made for the Unreal Engine going from 3-to-4 wouldn't be that hard. (Since the scripting sould be mostly the same between Engine gens, the only thing that needs to be changed is the parts that they added to the Engine for the game) The thing is they would have to optimize the UE4 engine for the Wii U since Epic doesn't offer it optimized for the machine which would eat up a bunch of time where it would be probally more efficant to change engines entirely.

The graphics are pretty bad, and the gameplay doesn't look like my cup of tea at all, but at least it will help diversify Wii U's library.

Upgrading to UE4 would likely cost more than the end result would be worth.

It still has a year. Hyrule Warriors used it's year well. This likely will as well.

For what ? 

The biggest change in Unreal Engine 4's shading model is the inclusion of applying a microfacet based specular highlight model to the surfaces of the the material. I highly doubt the WII U could handle anything beyond blinn phong for AAA games. Another big change is the capability to use layered materials and that comes with a noticeable impact on performance. 

He's not totally wrong in saying that the WII U wouldn't make use of a lot of the capabilities that Unreal Engine 4 can provide. 

It's not always the engine that defines technical feats of the games but it's about their technical qualities. A game using bad textures with a next generation engine doesn't mean much. Even if the WII U could run Unreal Engine 4 the games would still look no better than the original Crysis on PC. 

Although to be fair, most Xbone/PS4 games I've seen don't look any better than the original Crysis on PC maxed out. That game was so far ahead of its time  it's crazy.

I didn't like the game at all at first, but it has potential

To be fair - I think the game was recently moved to the Wii U, hence why the lack of polish in the visual department. I did watch some gameplay, and it looks fun. The boss battles are probably gonna be the highlights.

Itagaki is a pedigree designer - don't be surprise that the game will look much better in future trailers. Just sayin