I believe the difficulty has more of an effect on prices than most people realize. The majority of coins that trade on a daily basis come from miners cashing in, and that is pretty much the source of what little liquidity we have. While it is true that increased difficulty will not change the amount of coins found on a daily basis, it will shrink the amount found by the majority of miners, especially those using low-hash gear. Few people will cash in with 0.00004453 coins due to exchange fees. They will stack the coins until they have a larger sum to exchange, effectively draining liquidity.

I expect a slow but steady increase, lagging the difficulty spikes by a week or two.