Even the biggest Jason Mraz fan on the planet would have to admit that "I'm Yours" is a terrible choice for DDR - not only is it super slow (not necessarily a problem if it were an original song crafted for DDR), but it just lacks the kind of beat that makes you want to step in time with arrows. To compound the issue, the arrow choreography on many of the licensed tracks doesn't match well with the songs, making them even less fun to play. Of course, the track list has its share of original DDR songs as well, but hardcore DDR fans should be annoyed at how congested the list is with top 40 pop music (of which many of the tracks are arguably pretty crappy to boot).
Even more annoying, the majority of the original DDR songs need to be unlocked through clearing the initial track list, whereas all the licensed drivel is available from the get-go. On the plus side (sort of), Konami plans to make available various DLC tracks via an in-game music store, so there's that.