A lot of people are saying the pay rate shouldn't be the same for all members. Is this because you believe if I make different rates based on rank then the rate will go higher for upper ranks? The only thing having a different pay rate will do is take money away from the lower ranks, it won't change anything for Legendary/Hero.
They are just suggesting rank based pay rates because higher the rank more the signature space you get.
But it depends on the one who manages it and I too don't think same pay rate for all the campaign participants which give space for HQ low ranked poster to earn same as HQ high ranked member.