I don't think any of the "dislike" for what SW is doing now (from the people who wants PT back) comes from the albums actually being bad quality-wise. It's not like Raven is a bad album or anything. I remember when he released Insurgentes, the feedback overall seemed very positive. Maybe it was because he was still in PT as well, so there were no backlash in the same way. But then PT disbanded and now he has released Grace and Raven. Either you buy into the whole 70's prog rock with a more retro sound, and you really love what he is doing, or you might not find the direction he is taking very interesting at all. To me, Raven is a fine album musically, it's just not a very exciting road he is taking with his music. But that's just my opinion. He has gotten a lot of new fans with this album, probably fans who are very much into the more classic sound, and really appreciates what he is doing.
As for who I would love to see him collaborate with, I would say someone that isn't part of the progressive scene. Would be cool to see what SW could do with someone like Trent Reznor or Mike Patton.