The existence of E (as this thread speculates) will force those who want miles/status to pay for it through higher fares that earn miles. It would further move that way if the speculation of a change to LUT earnings becomes reality.
But that doesn't get at the inherent disparity of cpm in different markets, and different tickets within the same market. I guess lumping together LUT as partial credit, HQK as 100%, and YBM as 150% sort of gets at that last part, but not as elegantly as "you get 1 point per $1 spent", the approach used by (eg) the hotel and credit card industries.
Actually, a split RDM/MQM approach similar to the split RDM/EQN approach used by the hotels might make sense... link revenue awards (ie: RDM) to spend but link status (ie: loyalty) to frequency (MQS/MQM).