I understand it, but I almost wonder if getting Carey version on would be easier initially. Then could work backward possibly to the earlier ones.
Easier, maybe, but not necessarily a better choice. Look at what GSN is doing with the Harvey Feud--it's an overload. The allure of oldschool GSN for me was being able to see older versions of Feud alongside the modern one on the air (still Karn in those days). It let me enjoy them both in their own way without it getting stale. As it is, I'm surrounded on all sides by Harvey's Feud, and I've gotten to the point where I don't even really want to watch it anymore.
I think having the Carey version re-airing anywhere else, at least for now, would have the same effect. Viewers who miss Bob aren't really getting anything, and the overexposure risks turning off casual viewers who don't much care for Drew and some of the other changes since season 35 wrapped, but still enjoy the basic format enough to try it. (Speaking for myself: if I don't like season 47, but did enjoy season 35, I might've enjoyed the first half of season 36, but that's about it.)
On the other hand, if they start re-airing Bob's old shows, it'll give classic fans something they can enjoy, and as long as it doesn't air opposite the current show, it wouldn't take anything away from CBS.
(Put another way: folks who liked Bob but not Drew already aren't watching the regular show on CBS, and folks who got bored with Bob's show probably wouldn't tune into reruns of it but would stick with Drew's show. Either way, there's a constituency that's not getting served: classic fans. So if you air Bob's shows, you're giving classic fans what they want, without taking anything away from fans of the more modern incarnation.)