What a date at ProgPower for SA or NW can offer fans that their regular tour cannot is guaranteed access to the bands for autographs and pictures. If the upcoming NW/SA tour is like the last NW tour, it could be very hard to meet any of the band members. In Chicago, NW stayed in a hotel away from the venue and were driven in and driven out promptly before and after the show. Tarja doesn't even take the bus with the band (and I don't blame her), prefering to travel separately with her husband via plane when possible.
I certainly would like to see SA at PP6 (not to mention NW again).