I don't know that it really matters. Clearly it's going to be an issue as far as their ability to get multiplatform games going forward, but on the one hand Nintendo hasn't had good third party support for almost 20 years now anyway. On the other, multiplatforming is industry standard now in a way that it really hasn't been before, so they might actually be missing out.

I'll cheat and say they should have provided more software. Getting a headstart on the competition only really helps if you actually do something with that time, but having this terrible lull from now until... who knows when? The holidays? It's just a squandered opportunity. Bringing out all their big guns just as the PS4 and Nextbox are launching will probably be like pissing in a typhoon.

Battlefield 3 is running on PS360 too but the versions are completely different compared to the PC Version.
Smaller maps,less players,not anywhere close near the "BÄM" Effect of Details and all that stuf  BUT the PS360 are able to run a version of the game.
Same goes for Witcher 2 on PC and 360 - The 360 Version isn't even running on Low PC Settings but it is there.

PS360 will do the same with WatchDogs and the WiiU will be somewhere between them and the PS4/NextBox/PC versions.
Transition games aren't really a big grade to messure cause there are "Both Gen" Versions anyway.
The time when those games are over and the New Engines will be used for real you can talk about that - Right now most developers don't even have DevKits that are able to use anywhere near the full potential of the PS4 and it is probably the same with the NextBox.

it may not be on par with next xbox and PS4, but i am counting supremely better that 360/PS3. My evidency is Need4Speed version on Wii U, that used PC assets. It should be good looking enough the steal some sales to last gen consoles, and other next gen consoles (because of console cost). Development for it shouldn't be that painful being already up and running on Wii U, while last gen versions will start after next gen consoles version. This two things alone indicate, to me, that Wii U won't get some ports because of business decisions not technical ones.

The problem is that your evidence isn't even out yet.
It does use PC assets, but it could still have framerate problems, lower draw distance or lower resolution. We should wait for the release first.

need for speed is made with currentgen in mind you can you that from the pc high settings vs 360, they are very identical, here are some pics from df, while watch dogs is made with a high end PC in mind, huge difference.

Nintendo just has a better relationship with Ubisoft than other publishers.

I am basing my opinion in terms of development for Wii U. Just from the fact that PC assets were used on Wii U it means Wii U is next gen and it will look better and run better than last gen consoles. It needs to be refined more that next gen is understandable, but there is no reason why next gen games will look on par with last gen games. Still to be seen for sure, but that is my opinion so far.
edit: criterion said they used the high end pc assets!

Watchdogs is coming to the current gent consoles as well so the Wii U version should be just on par or just above those. The Wii U's values will be based on their exclusives and Nintendo will need a whole fleet of them to take peoples eyes away from the PS4 and 720.

those pics i posted are pc max settings but with 720p resolution, many of those effects will no be present in the wiiu version, i have seen many 360 mulit-platform games show a bigger jump vs the ps3 version, then what i'm seeing from the pc version vs 360 version.

Actually Ubisoft is generally very good with everyone. Everyone gets exclusives when the time is right (Excluding PC).