Champions with origins tied to the League...
 

We need more of them.

While you (Riot) may add new regions and places as you see fit depending of a champion's concept, theme and skillset, I believe that the best foundation of inspiration for new champions is being left out, and that's the League of Legends itself. For a world where magic goes rampant and bestows a wide variety of powers to all sorts of living and non-living things, the folk involved with the League sure do remain unaffected.

People that made their careers in the League (such as Jax), conflicts involving Summoners, failures in the system (like serv...err, nexuses crashing), creatures born in the Fields of Justice...I see plenty of opportunities to create new champions out of the very foundation of the game. But obviously we need more ninjas and pirates.

Jax was an acomplished warriror before the league and he is the ONLY one who is more famous for his post league exploits. I agree with your overall point of how people who are closley tied to the league can be made(it's 20 years old so someone cna grow up with it)

The recent JOJs show champions like Kayle moving toward a stronger affiliation with the League. Also, an affiliation with the League is inherent with each and every champion, especially considering that the League functions as the arbitration mechanism for the client city-states. Nevertheless, you will see more champions become more involved in the League's business as the story develops.

And yes, we do need more ninjas and pirates. Pirates more than ninjas, obviously, but your sentiment (sarcastic or not) is duly noted!