It is completely unknown wether the plugin would change the editor or not. However, that would completely exchange the grid to a different, fixed size - it is possible to program plugins for variable grids, but that would require a lot more work.
Since it's already confirmed that the entire engine is open and accessable, it should be relatively easy (as in requiring only days instead of months) to modify the engine for another grid size. And the plugin control detects those files automatically and offers an interface (that somehow has to be defined by the scripter) with the neccessary values for setting up the script. Instead of placing the script text into the script editor, the script file is placed into a folder. Unfortunately I also can only guess, but from what I have seen and read, the 'plugins' are basically a more formal way to handle regular scripts.
