Patrick Stewart is a better actor
The thing about James Tiberius Kirk that makes him not nearly as great Jean-Luc is the fact that Kirk has William Shatner portraying him while Picard gets the Shakespearean great known as Sir Patrick Stewart. That’s not to say that Shatner is terrible. He’s just no Shakespearean actor.
Sir Patrick Stewart brings nuances to the character that Shatner could only dream of. And he does it with such a subtle shift of his eyebrows or the way he speaks. It is truly impressive to watch. And then, there is William Shatner.
Honestly, he probably got the role of Kirk because of his looks. That or the casting director really loved broken speech patterns and watching a grown man pop a blood vessel any time he was supposed to act angry.
With Stewart, it is just so much easier to watch and enjoy. He just seems to be as ease in the role and nothing is forced. It also helps that it seems like Patrick Stewart enjoyed playing Picard while Shatner seems to hate that he is always related back to Captain Kirk.
No matter the difference, Patrick Stewart is one of the reasons that Picard is one of the most loved captains of all time.