Suggestion: Color/texture replace
It would be useful to have a function like Ctrl+Shift for recolor/texture, but instead of changing the entire grid it only changes blocks that share the same color/texture. For example, if you have a stripe going down the length of your ship you could change the just the stripe color and not the whole grid.
I'm really indecisive and like to change my ship colors often. Hopefully others would find this useful(?)