presence from the off

TV Rick Berman Talks 18 Years of Trek In Extensive Oral History. Surprisingly candid. TrekMovie offers some notes:

Billy Campbell cast as Riker, but Pike didn’t feel he had command presence, so went with 2nd choice

Gates McFadden fired at end of first season because head writer Maurice Hurley "he had a real bone to pick" with Gates and din’t like her acting, Berman brought Gates back for 3rd season after Hurley left

Whoopi Goldberg initially wanted to replace Gates McFadden as ships doctor for Season 2, but it was felt she wasn’t right for that role so they created new "Yoda-like" character of Guinan

Much as Frakes grew into the role, Billy Campbell would clearly have been a more interesting presence from the off -- he turned up in the title role of the second season episode "The Outrageous Okona" and stole every scene and turned an only ok episode (like most of the first couple of seasons) into a great one.