So Picard, the character, would've been captain of the Stargazer from 36 to 58 years of age. That would mean Marcus Nash at around 38 would be about the right age as Picard in the early years of his captaincy of the Stargazer. He could be right for the role.
No, you're forgetting there was a gap of over eight years between the
Stargazer and the
Enterprise (a gap covered in my novel
The Buried Age). Picard was 27 or 28 when he took command of the
Stargazer, and the ship was lost shortly before he turned 50. (He's usually said to have been 28 at the time, but
The Buried Age establishes that he'd commanded it for slightly over 22 years and lost it two months before he turned 50, so by that formulation he would've been 27.)
And I doubt there would be any great interest in a series about Picard on the
Stargazer. General audiences would want to see Data and Riker and Worf and the rest.
Besides, Marcus Nash didn't even have any lines in his brief appearance as young Picard. He was little more than an extra. And he only has two other acting credits on his
IMDb resume. And he's not British (he's the brother of Jennifer Nash, who was Meribor in "The Inner Light" and who didn't have a British accent).
If Picard is ever recast, he almost certainly won't be played by Tom Hardy or Marcus Nash or David Tristan Birkin (from "Rascals"). He'll be played by someone who's found in a lengthy casting process and is chosen as the best actor for the role as it's defined in that particular production.
