What if it had a different host?

Was Levar Burton the first choice for the host? I would have picked Leonard Nimoy as host for the show. Would he have made a good host for you, or are they two very different men personality-wise? I know I didn't like the re-vamped version of In Search Of... because of the host, but the subject matter was great! I would have picked him as host for Unsolved Mysteries and/or Beyond Belief: Fact or Fiction, but now that I think about it, I can't think of anyone else being the host of those shows but Levar Burton, Robert Stack (later Dennis Farina)and Jonathan Frakes. I wonder if Leonard Nimoy *was* offered the chance to be host of those shows? Just thought I'd ask your opinions.