smilelys, lunar and solar max out to where you only get a 20% boost. I thought the same thing as you, until they stopped leveling :(.
This is a really addicting game, but it doesn't have a point, seeing as you could technically, with enough time, replay levels as much as you wanted and have an unlimited source of AP.
I'd like to see some badges :)
 "Apocalypse"){kind=icon}