Because of the added "efficiency" to pumpkins that was implemented into axes at the 1.0 release, I expected the same would be done for melons, but it has not been. A fix for this is extremely simple and would be a great thing to see in a vanilla environment without having to implement it myself.

What actually happened was...:
Here I am using a sword to break a melon block instead of an axe because it's quicker, when in all reality it should be quicker to use an axe.