Since it's somewhat on topic (and I tend to be OCD about this kind of thing), here are the hosts who'd had network shows cancelled since the beginning of 1973 as possible Blyden replacements. Let's eliminate anybody who had already been hired to host another network game in the interim, as well as Joe Garagiola and Dick Enberg, who were likely both under contract to NBC due to their sports announcing.
- Jack Barry -- not a good fit, and unlikely that G-T would have considered them after how his brief time working for them went.
- Jack Narz
- Bob Clayton -- not likely he was under consideration, and it seems he was tied to New York, given he turned down the opportunity to host the syndicated version of Concentration after NBC dropped the show.
- Art Fleming -- bad, bad, bad fit.
- Bill Cullen -- staging issues aside, if Cullen turned down moving from New York to do The Price Is Right, I don't think he'd be interested in moving cross-country to host Showoffs, either. (Also, Blankety Blanks may not have been officially cancelled at that point.)
- Allen Ludden -- not as bad a fit as Fleming, but not a very good one, either.
- Jim Peck -- no obvious strikes against him, other than G-T tended to hire hosts with whom they were familiar.
- Nick Clooney -- same as Jim Peck, but it appears he turned down at least one other game show offer around that time. That may have been around the time he moved into news, which would have required him to be in Cincinnati full-time.
I wonder if anybody ever thought, "Hey, what about Richard Dawson?"
Ultimately, I don't think Bobby Van was the reason
Showoffs didn't make it -- multiple rule changes during a six-month run are never a good sign.