Keep in mind TNG ran for a more then twice as long as the original series. Gives it a lot more time to flesh out its cast of characters. Originally Picard, Riker, and Crusher were envisioned as the main trio, but all of early tng’s production issues and Gates Mcfadden leaving for the 2nd season threw a wrench in that vision. Starting with season 3 the show becomes more of an ensemble. You start to get the formula of specific character-centric episodes that will stick with the show for the remainder of its run. Honestly it feels like near the end of its run TNG was more the Picard, Data, and Worf show. Riker gets hardly any episodes that focus on him in the last few seasons.