The photoshop action scripts are very good, but the real solution, the professional way, would be programming-scripting. There would be an infinite number of functions and tiny smart ideas for the community.
I use another program for design, iDraw (now Graphics) .. it is able to access Java, a set of programs and other systems... this is greatest strength, I would like to use something similar in Pixelmator here.
One more thing ...
Uncomfortable to always work with two programs at the same time, other settings, copy / paste, save-open .. If Pixelmator develops on vector tools, then this would be the best program that wouldn't be needed for another.