Of course I'd see it if it does come out but I don't really see what direction the series can take at this point. I mean the last Saw movie was sub-titled "The Final Chapter" implying it was the end (but then again so was Friday the 13th IV and that wasn't the last film of the series). I'm totally fine with it ending at VII. That was more than enough actually. And Saw VII answered the big question, the main thing that kept me watching these movies, and that is, what happened to Dr. Gordon. That was their biggest mystery and they already revealed it. They had purposely waited to answer that question for the final film.
So long story short: I'd go see it simply because I've seen all the others but I'm not on the edge of my seat with excitement about it. I wouldn't be disappointed if Saw VIII doesn't get made. The series had a good run.