maybe a better way is to "hold" any block for a given amount of time, after it is solved. No payout immediately.
What about random interval schedules? If the miners don't know exactly how many coins they'll get or when, they'll mine forever and it will be random just who gets how much of what. This would create a maximization of mining resources while discouraging the ASICs.
Think of it like an RPG where if you use the best weapon in the game (ASICS) it might not work on every monster which spawns. Since you wont know which monster will spawn, you wont want to use just any weapon but have them all. And since you don't know when that rare monster will spawn, you'll have to hunt in that area for as long as it takes until it spawns. Think of Dragonquest with the metal slime. Think of Final Fantasy with cactrot.