... have the character of Trip be the Captain of the Enterprise ...
Okay, why not? Enterprise was on the air when I was in High School, Trip was the single most popular character with that age group, my friends in their twenties felt the same way. What demographic did Archer bring to the table?
Trip was everything Archer wasn't, he was (usually) calm, confindent, laid back, smooth. He was comfortable in his own skin, which is somethong that Archer very obviously
People naturally liked Trip.
He was a southern gentleman (with the sexy accent that went with it).
He got the women, even the resident Vulcan chick.
He played the harmonica.