I'll preface this with saying that I'm only going to do the "big 4" (minus J!) and Pyramid because, while other shows may have had many hosts, they were in different versions that, in my opinion, were different enough to where we may be judging the host against the version of the show instead of the host on his/her own merits. As an example, for Match Game, comparing Rayburn to Shafer, to me, is like apples to oranges because Shafer's version had such dramatic differences in play. Similarly, I don't think it's fair to compare Trebek to Probst for J! because they hosted very different versions of the show, aimed at different audiences. Of course, YMMV.
That said, here are my rankings:
TPIR: Barker, Carey, Kennedy, James, Davidson (Carey at #2 due to his longevity and carrying the show nicely into the 21st century, James at #4 because I just didn't like his more "traditional" style of hosting for the show)
Wheel: Sajak, Woolery, Goen, Benirshke (Goen and Woolery are a toss-up to me, but I disagree with those who say Sajak "phones it in"; I rather describe it as being on "autopilot" and instead runs it like a well-oiled machine)
Feud: Dawson, Combs, Harvey, O'Hurley, Karn, Anderson (The last three are way down the list, IMO, but I rank Dawson as #1 slightly ahead of Combs due in part to lasting longer than Combs but also knowing how to take the seriousness of the game in balance with the goofy answers the best. Harvey is definitely an excellent fit for the modern-day Feud, but he still hasn't quite found the balance between serious game play and hilarious "YouTube-worthy" answers, although he has gotten better.)
Pyramid: Clark, Cullen, Strahan, Osmond, Richards, Davidson (Again, the last three are way down the list; to me, both Osmond and Richards felt too wooden, and Davidson...'nuff said there)
My wife and I actually spent the better part of a night out discussing these rankings, so kudos to the OP for interesting dinner conversation!
\beats discussing bills
Anthony