If we take the "gray universe" version first: I have nothing against Bujold as an actress but this would never have worked. Everyone should be happy that Mulgrew got the job.
As for the Star Trek universe version of this:
Nicole Janeway, who can be found on some Youtube clips instead of Kathryn Janeway is actually Kathryn Janeway's aunt. A sister to Kathryn's father Edward Janeway.
Interesting!
Contrary to most members of the Janeway family, Nicole Janeway weren't interested at all in Starfleet and space exploring. She always considered her brother Edward a crazy fool who should have chosen another career instead of Starfleet.
"Man doesn't belong into space", she often said. "It's utter foolishness to travel around in those metal boxes in such dangerous environment".
When Edwards daughter Kathryn decided to join Starfleet, Nicole was furious. "You are a hopeless, reckless fool", she told Edward Janeway. "But worse is that you have raised your daughter to become one hopeless, reckless fool too", she said. And added, "This will end up in a disaster, believe me!"
Nicole Janeway often expressed her compassion for Kathryn's mother Gretchen. "I really feel sorry for her, marrying my stupid brother" but expressed sympathy for Kathryn's sister Phoebe who had chosen to become an artist instead.
When tragedy actually struck and Edward Janeway was killed during an exploring mission, together with Kathryn's fiancée Justin Tighe while Kathryn survived the accident, Nicole Janeway pestered everybody who wanted to listen with comments about "well, what did I say". Finally Phoebe Janeway got tired of hearing her aunt's complaints, lost her temper and told Nicole Janeway where to go.
When Voyager dissapeared in the Badlands, Nicole Janeway continued to tell everyone (except Gretchen and Phoebe Janeway who had broken all contacts with her) that Kathryn only had herself to blame for being as foolish as her father. Due to her not too diplomatic comments about certain family members, Nicole Janeway became rather isolated from the rest of the family. She continued to live on her ostrich farm in Colorado while keeping her negative opinion about space exploring.
The scene with Nicole Janeway as captain on Voyager was actually a nighmare Kathryn Janeway had two nights after Voyager left Ocampa, heading for the distant home. Only in a nightmare could Kathryn Janeway imagine her aunt as the captain on her ship.
(From the Kes Webpage, the side "Voyager Mysteries-and how to solve them)
Well, I even think that he considered himself to be more, a potential suitor at best, a friend with benefits at worst! It could have been interesting and very funny to see especially in the light of nature. And Chakotay would have had enough to choke! 
