Star Trek: Voyager was a hit show for seven years, and while fans were up and down on it during its initial run, many have come around to see just how good the quality presented actually was. It became a hit on Netflix and the renewed interest allowed many of the past-stars of the franchise to appear on other Star Trek shows.
Jeri Ryan (Seven of Nine) was a main player on Picard, Robert Duncan McNeill (Tom Paris) appeared on Lower Decks, while Kate Mulgrew (Kathryne Janeway), Robert Beltran (Chakotay) and Robert Picardo (The Doctor) appeared on Prodigy. The show has seen so much love in recent years, it's hard to imagine anyone playing any of the other characters on the show.
Yet, had Picardo stuck with his initial instinct, that's exactly what would've happened with his character, The Doctor. Speaking to Star Trek.com in 2022, Picardo revealed that he passed on trying out for The Doctor because of the apparent limitations that the role presented to him.
""I turned down the audition for The Doctor, because it just didn’t sound interesting. It sounded like an automaton. I read the script and I liked Neelix, so I asked to read for Neelix… and then I didn’t get Neelix [laughs].
The Doctor was cranky, and I didn’t know why he was cranky. I didn’t understand the role at all. I faked my way through the audition and ad libbed a DeForest Kelley joke without knowing it was a DeForest Kelley joke. My last scripted line was roughly, “I believe someone has failed to terminate my program.” I added, “I’m a doctor, not a nightlight.” I ad libbed that line, which you shouldn’t do in an audition, but it got a big laugh and I was hired the next day. Then I had to figure out what the role was.""
Considering how well Picardo and the Doctor character has aged in recent years among the fandom, it's hard to imagine anyone else playing that role. Or more specifically, Picardo playing any other role than The Doctor. I'm more of a fan of Neelix than many, but I felt Ethan Phillips did a great job as Neelix and few could've made the character even more likable than Phillps had.
Picardo was born to play The Doctor, and seeing him try to play Neelix would've been peculiar, to say the least. We're grateful that Picardo got to play the role he did, and history will support that theory. After all, just ask anyone who their favorite character from Voyager was, and they're likely to tell you it was The Doctor.
Seeing how smoothly he introduced an ad-libbed portion of the dialogue really shows you that, without understanding the idea behind the character, he still understood the character at its core. How many others can say that?