I sound like a crazy person when I say this but like half of the changes from SC1 to SC2 were my idea lol. I really wanted to see SC2 but he was like, "how would we change it enough to be a new game" and I was just listing stuff off for literal days. It was so surreal when the game came out because it felt like I had somehow spoken it into existence. Of course I didn't have anything to do with the storyline, single-player campaign, world-building, and stuff like that.
I'm pretty sure my friend pitched them all as his idea and leveraged his career a bit, which is fine obviously, as the ideas were worthless without someone to pitch and implement them. He's been retired for a while now... wonder how he's doin.
We also talked about D3 a lot (making custom resource pools like League of Legends / WOW did) and I even pitched the pilot idea for Overwatch (an upgraded version of Team Fortress with custom heroes).
RE: Single Player MMO?