Now I remember a few people saying they couldn't talk about the WiiU because they were under NDA. But now they should be able to because the console is out now.

So,

1. is the WiiU as powerful, less powerful, or more powerful than the 360 or PS3?
   
2. are there any challenges in porting a game from the 360/PS3 to the WiiU?
   
3. is the WiiU just the Wii + a power up or are there significant changes to the WiiU?
   
4. is anybody planning to support the tablet in their games?
   
5. how important is the tablet in the game dev process?
   
6. is there anything about the WiiU you would change from a software or hardware perspective?
   

While I've never been under any NDA (probably due to the fact that I don't have any actual inside information on the Wii U... or anything, really), I've been doing my darndest to keep up with the news on the thing.

I feel this article puts some perspective on your first few questions.

As for the fourth, I may not have any plans, but I sure do have dreams.

But now they should be able to [break NDA] because the console is out now.

The 360/PS3 have been out for years, but their NDAs are still in effect... I'm careful when discussing their hardware to only mention details that are already present on wikipedia.

The WiiU fits in a similar performance bracket to the other consoles, except it can push more pixels and has more RAM, but might have to move as much CPU-work over to its GPU as possible in order to cope with its relatively slow CPU CPU GPU RAM(size) RAM(speed)
#1 PS3 WiiU WiiU 360/PS3*
#2 360 360 360/PS3* PS3/360
#3 WiiU PS3 PS3/360 WiiU
...
#4 Wii Wii Wii Wii *hard to pick winners in 360/PS3's RAM. PS3 has the annoyance of being physically split, but in some situations this can actually be a good thing. Overall, they're close enough.

Expect the PS4/"Xbox720" to leave it in the dust, performance wise.

CPU looks archaic, multi core version of Wii's CPU, which is already pretty old by itself and its based on technology that was already old when the Wii was launched.

The GPU on the other hand looks pretty nice. Im guessing they want simple and good looking casual games?