DS9

Sisko was definitely a fully fleshed-out character. He balanced action (Kirk) with wisdom and subtlety (Picard)

He stood at the gate between the federation and oblivion by a greater force, and managed to hold his nerve, and his poise

All while being a good father

Add Quark, Garak and a host of other characters who have complete identities of their own, and it’s a winner