Well, let's look at it this way: How likely is Nintendo to use roughly if not exactly the same MLD0 format that +100 Nintendo-licensed Wii software titles already use? Very likely. The only tough part will be figuring out the new archive compression, but only if it is different.
Not very likely roughly or exactly the same as MDL0, I remember Nintendo stating that their team was already in full capacity for HD gaming, this probably means some internal changes to ensure quality were made. Granted the MDL0 format will be in some ways similar to the new model format, but I believe there will be changes in shaders, overall structure to support higher polycounts while not wasting more space than needed and the texture format, which is sure to change now that it allows for full color images. Also, while the first step is hacking the Wii U remember that not even the disc structure has been touched, no one has reportedly dumped a disc to even find out the compression.