This is not what classic mode is about. The reason you play classic & other game-modes than normal is because you want a challenge. I do believe certain incentive should come. But just like any other mode it should be from events. Just like the tournament we just had this weekend. It makes no sense to add higher drop rates to and already growing economy for classic players.
True, but if more and more players keep leaving and cashing out for regular GP than there wont be much of an economy, or players to sell to / buy from, it's already a struggle to buy basic items.