I finally got together with three friends and we played the hell out of all 6 of the multiplayer games. Despite my initial misgivings from a demo, I actually enjoyed Zelda Battle Quest a lot. Playing with people you know most definitely helps things. And the other five games were great as expected, including Pikmin, Metroid, and Mario, which I hadn't had a chance to try previously. Metroid Blast can feel a bit overly chaotic at first, but after a few rounds you get a feel for it.
I still don't know if this is a good $60 package, but it hardly matters to me at this point. I was never not going to get the Deluxe Wii U, and as a pack-in, it's awesome. If only it were pre-installed, then that would have been absolutely perfect.
Unlike Wii Sports, I'm actually really into these games, so I'm going to see if I can convince my family to play. I think they'll really enjoy some of them.