HDTV is nice, true, but not at the extra expense for Nintendo. Plain and simply the Wii is not about bleeding edge graphics and super high resolution, it is for playing fun, innovative games.
Small Tv's will be fine, the sensor bar will not change and that is what records your movement of the wiimote. I believe it will be easily callibrated so nobody should have trouble getting it set to work correctly.
A good game does not need blood, nor an M rating. A good game just needs to be, well, a good game. Any Mario title is a good game, no?
Processing power is fine. The developers can work with what is availble easily, and you will see a plethora of fantastic titles. If you want top of the range graphics, get a PS3 or XBox 360. If you want a fun system, get a Wii.
I believe it has been discussed on these forums that you will be able to connect to the net using USB Ethernet.
And finally, we don't know if those mock up controllers are real until Nintendo announces it. I'm sure if they were legitimate and final we would indeed have seen them at E3.