Picard is both the writing and Patrick Stewart. Picard would not be the same character if they'd cast Kevin Sorbo to play him[1]. Picard without Stewart's presence and gravitas would be something else entirely.
[1] Sorbo's portrayal of Dylan Hunt is basically just taking his Hercules role and putting him on a space ship and I have no doubt it would look the same on the bridge of the enterprise.
[1] Sorbo's portrayal of Dylan Hunt is basically just taking his Hercules role and putting him on a space ship and I have no doubt it would look the same on the bridge of the enterprise.