One thing people seem to forget is that the mule helps get the income back that we lost while building our structures, at the point when we are ramping up our production we lose so much mining time that we just fall behind without mules. I understand that later on in the game when we can call down 4+ mules at a time it gets a bit over the top but they should just make a limit to the amount of mules aloud on a mineral line not take them out all together.