Alex Trebek's game show hosting gigs included High Rollers (in which he had to read multiple-choice questions, giving the answers first), Double Dare (which, from the Wikipedia article, was not far off from Jeopardy in its intellectual demands) and the 1980s version of Concentration (a game show originally hosted by newscaster Hugh Downs, running concurrently with the original Art Fleming Jeopardy).
I have no doubt that this pedigree was the major reason why he was chosen for the present Jeopardy (which Art Fleming, by then quite old, had turned down).
In the first years of Trebek's tenure on Jeopardy, comparisons to Fleming were inevitable (which is probably why the present Jeopardy has always been a bit reticent about even acknowledging the Fleming era), but Trebek's erudition, modesty, and good humor quickly won audiences over. I really don't think Mike Richards possesses any of those qualities.
Many people have said that despite Trebek's efforts to avoid making himself indispensable, Jeopardy would likely fail under a different host. I've pooh-poohed that assertion, but if Mike Richards ends up as the new permanent host, I think it may come to pass.
