Working at Riot is extremely collaborative! From inception to execution everything is team-driven. Our Product Owners represent the player's interests and the rest of the team share their ideas/excitement. At every stage what enables us to decide to move forward with a project is this one question; "Are players going to love this?"
We don't really have supervisors but are empowered to champion ideas we ourselves believe in. At the same time with great power comes great responsibility, and we each do our best to understand our players and what will get them excited. That's why it's so important for us ourselves to be players; I play a lot of whatever champion I'm working on so I can really understand what is cool about them.
It can be difficult for new Rioters - you look around for someone to give you the thumbs up or 'ok' so you can pull the trigger and everyone just points right back at you: it's your responsibility and if you get it wrong then that's on you. I think it's an awesome way to work. Over the past 18 months I've made mistakes I've learned from and I've had victories where I go home pumping my fist at all the positive feedback on s20
, forums, reddit etc. but the whole time I've been able to decide when I think I've got something players will love instead of being just a tool in a production pipeline.