I don't think playing "hits" are the issue. They're not suggesting they're just going to play hits sets. In fact, I suspect they won't. They're just saying they'll be sticking to the same set for a tour.
Also, having seen Mangini play, I honestly have no desire to see Portnoy back. Mangini was awesome.
17/7 Ripper Owens
18/9 Theater Equation
26/9 Ugly Kid Joe