PS3 and Xbox 360 SDK's offer the Unreal 3 engine, Havok and Agiea PhysX and a wide array of assorted tools.

What Nintendo offer in its SDK ??

Imagine Call Of Duty using the Prime Engine !!!!

Mortal Kombat using the Smash Bros Engine !!

Need For Speed, Nitro Bikes using the F-Zero engine !!   etc ...

You cant expect much for 2000$, but nintendo could license their middle ware to other dev's so that they could make better looking and controlled Wii games with a faster turn around time.

UE2, Id's last engine, and all the engines produced in the last 10 years are still available. Would you mind if your Wii games looked like Doom3? It can handle it, and that engine is still available. 

But the dev's will still have to port it over to the Wii.
Epic and ID do not officially support the Wii. Dev's have to tweak the engine for the Wii.
Sony just signed a deal to optimize Unreal 3 engine for the PS3.
Nintendo could either help out dev's by licensing their engines or sign deals with engine makers such as Epic and iD to optimize thier engines for Wii.

Ubisoft did not get any help from Epic then they decided to use the U2 engine for Red Steel.

Heck lucas soft actaully managed to port the U2 engine to the PSP for Battlefront 2 on PSP. I suppose it should be possible to port the Doom 3 engine  or even Unreal 3 engine to Wii

A good deal of studios use their own in house engines anyways and they can generally work with all three (and handhelds in most cases).

True, but why not help people out more anyway? This is like arguing: "Well, most people wouldn't use it anyway, so its not worth it." Even if it only helps a portion of developers, it's still a good thing. 

It would be a smart for Nintendo to continue to capitalize, as much as possible, on their advantage in terms of development costs. Keep pruning those costs down to bring in more developers.

As an actual developer I can full heartily agree that I WISH that Nintendo would release their Engine for 3rd parties.
What sucks the most is that for small budget dev studios like the one I'm part of we don't have the money to throw at a really nice engine like the Doom3 or UE2.5. It would really be nice if Nintendo would offer them to people at a much cheaper price.

Right now the choices with Nintendo have been the Doom3 or UE2.5 (or a few other $$$$) engines or write your own.

Sounds like this is a perfect opportunity for EA to revive Renderware, and drive middleware sales for the Wii. I assume its available for the Wii (anything that was available for the GC, should pretty much work with minimal upgrades needed).

I makes me wonder why EA killed renderware. It was the most popular 6th generation console engine.

The only thing I've heard of so far in terms of Wii development tools supported/offered by Nintendo is LiveMove from AiLive, which is not part of the SDK itself, but available separately.

http://www.ailive.net/liveMove.html