This whole state of affairs undermines bitcoin and is enough to destroy faith in the currency. Mining needs an overhaul, I don't pretend to know the solution.
Yup sky is falling. Or you are clueless. ASIC will fix the botnet problem. Botnet are useful for other things, once bitcoins becomes less profitable they will move to other things. You say there is no cost but it's not true since botnets can be sold thus opportunity cost. When the cpu/gpu nets go from producing 100+ coins a month to 1 coin a month you can bet they will do other things with the zombies.