Sounding a bit derogatory there to be honest. I see nothing wrong with saying what I did about Saw. The roughness DOES work in the theme's favour, just as people can say Colossus DOES now fit the theme with its rustiness. It may not be deliberate but these things sometimes just happen and work out.
I know it's personal preference but I would take a rough Saw, Colossus or Smiler over a super smooth ride like Air or something any day. Actually, that makes it sound like I'm hating on it, I'm not, but when I go on a ride I want to feel like I've done something intense and frankly brutal. I certainly don't want to relax in complete comfort.
As for the IP, I see no problem with it, it helped pull the crowds at launch and the ride is still going strong. Does a horror film IP have to be current then? I don't think so. It's a well known IP and will remain so for a long time.