Since we seem to be experts at wild, totally unfounded speculation here, I thought I'd throw in my own. I fully expect to be told I'm wildly off the mark, but it's just something that occurred to me, so I thought I'd put it out there for the rest of you to consider.
Having seen the pictures of Rich Fields at golden-road.net, it occurs to me that (a) he's a pretty telegenic fellow and (b) he's significantly younger than Bob Barker (which, I'll admit, is not a particularly difficult thing to be). Do you suppose that Fremantle chose Rich not just because he's a good announcer but because, in addition, they plan to groom him as the successor to the World's Greatest M.C.? If so, do you suppose we'll start seeing him on camera as we used to see Johnny and Rod? (Yeah, I know about the supposed Fremantle policy, but if my theory is correct, they'd want the audience to get to know Rich's face.)
Go ahead and rip my theory to shreds now (as if you needed me to tell you that).