Seconded on Gene Wood/TPIR.
When Johnny O died, G-T needed an announcer to get the shows in the can, so that was a temp job and I suspect Gene knew that. As for my takes on bad fits on hosts:
Louie Anderson for Family Feud
John Davidson for Pyramid and Hollywood Squares - he was okay on Time Machine
Patrick Wayne on Tic Tac Dough
Mike Darow on The $128,000 Question
Rolf B on Wheel of Fortune
Billy Bush on Let's Make a Deal
JD Roberto on Shop Till You Drop
Louie to me was inconsistent... some shows, I thought he was funny... other shows, he looks tired and wants to go home. Billy Bush had the same problems that Bob Hilton had on LMAD... he was trying to follow someone that was to LMAD as Bob Barker was to TPIR, and when Monty came on Bush's show to host a deal, Billy Bush couldn't help but look astonished at how easy and how much better Monty was. Never mind their attempts to make the show edgier... yeah it was distracting, but it took another 7 years or so for Wayne to finally find a way to make the show shine and not make anyone miss Monty.
JD Roberto wasn't really the problem with Shop Till You Drop... the mistake was getting rid of the stunts in favor of much less exciting and not in any way physical games that were just... boring. The bonus game was basically the same, but it lost a lot with its one level layout, and becoming some sort of Costco type store instead of a mall.
I guess I'll comment on Gene and Break the Bank. If you watch the first week of shows, Gene did seem to find moments to goof off and joke around in the prize vault, and another early episode apparently had Kline in an ape outfit making an entrance instead of Gene, but then Kline wanted a more serious tone, something Gene doesn't do. Gene struggled, and at one point didn't even seem to care, so they got Joe Farago, and honestly, I didn't think he was any better, and the show got much worse when they took out the stunts completely. Interestingly enough, Pat Finn mentioned with the TJW tryout that in another pilot, he was joking around more with the players, and Kline advised him not to do that. Finn was better with STYD, and didn't have to wear glasses like Kline insisted he wear on TJW, even though Pat didn't need glasses or wear them otherwise.