Make everyone have identical lag and no teleporting.

what you are wanting is completely impossible

What a totally badass suggestion, BUT a game cannot be perfect. sigh

Most lag actually happens while trying to communicate to a server.. your idea would not resolve anything on this area.

League of Legends figured it out. Their game is nearly perfectly lag-less for me. I can't stand Transformice cause I hop over a cannonball and then it appears back in front of me. It is possible, they just need to reduce the client-side prediction engine and make the level and all characters processed in the server with command events coming from the clients instead of having the clients provide the actual location processing. For example I was able to float in mid air by having my computer run super slow when playing Transformice. Cannonballs actually would go through me. That's cause the game is putting too much calculations on client side. It's just a bunch of bad programming by the team that made this game. Never do that kind of stuff client side.

This game is suppose to be amazing, not perfect.