If you were a player would you feel a bit jipped that you sign up to a salary cap but coaches are outside it?
News today that Ange may get 500k from Brisbane and Arnice wants the same to go to Sydney (the same as what Lavicka was on)
Marquee players are also outside the salary cap though, so it's not like coaches are the only exception to the rule.
At the end of the day players aren't coaches. They are in the players market and worth whatever they are worth in that market. If they want to earn what a coach earns (or CEO or physio or whoever for that matter) then they need to change jobs. And if they want to earn more as a player than what they can in the A-League then they need to become a better player (or get a better agent).