There should be a change...
I dont exactly know when but there should be...
Maybe when the reward in coins get to 25BTC instead of 50BTC?
Maybe even now.
It doesn't make sense to make such a change before bitcoin reach a stable value above 100$.
I like the method proposed in another thread (step by step). We could implement it and decide later if there's a need to change or not. Speaking in uBTC would be as acceptable to me.