By mid-level economy, do you mean player/npc interactions or player/player (eg: res/cst)?
To be plainly honest, the mid-level economy can go blow a goat. Mid-level economy is there to support mid-level characters. The reason to push xp up is to reduce the number of people in the mid(and low)-level lurch. I find it difficult to believe that people would be as willing to interrupt their leveling to get an updated weapon/spell if their xp gain remained viable.
/edit:
It should be pretty safe to assume only new players would be struggling to keep their wallets lined. It should also be pretty safe to assume that new players will continue to receive support in form of cash handouts as they always have. Returning players are in that same boat. As much as I love a new player, I love a returning even more.