It's just too bad they're wasting a headliner spot on Smashing Pumpkins if that's true.
NIN and QOTSA are my two biggest wants as well. However, an reunited SP would be very cool to see. Saw SP last summer and they sounded fantastic and had a very good setlist. If it's the original lineup you have to think it'll be heavy on Siamese, Mellon Collie, and Gish, which would all be awesome live.
Smashing Pumpkins | Soundgarden | Queens Of The Stone Age
Unless Soundgarden has new material I'll pass. Saw them last year and they seemed to be going through the motions for much of the set.
They have new music coming supposedly. Last time I saw them in 2014 I felt most of the band was just going through the motions as well. They didn't have Matt Cameron on that tour, which certainly didn't help.