Each square on a map has a reference, which is what we (without seeing it) use when marking up an 'area' in editor. We can actually see that when using the grid, we just can't 'use it'. I think that, as opposed to pixels when we draw a picture in some paint-software (or rather like it but on a bigger scale), when we landscape in Editor, a certain value of paint (and each must have a digital value) gets appointed to each square. So it really shouldn't have been hard to let us have the option to trigger 'I want this area to have this paint-value' whenever.
I guess it didn't occur to them, much like it didn't occur to them that we might want to re-skin objects, which is very difficult for us because they used the, very sloppy, method of using the same skin for multiple items. Even then, one would need to be able to use a 'copy of xxx' for re-skins to have much value for us. What are the chances that what I like a building to look like, is the same as what Peter or Paul want? Changing a skin only changes the look, does not add options. Now, having multiple 'copies' of a building for us to play with, would have been much more demanding on the programmers, although they do it in a way with the multiple version of some buildings. We just don't have the option of influencing what they look like.
Part of our 'problems' probably come from so much of this game being a re-use of parts of previous games (so much for unique). Like the colours. Whenever you use the 'cliffy', you end up with red mountains with green grass on top. NOwhere in Egypt do they have red mountains, and even if they did, they sure won't have green grass on top. Much of my time in mapping goes into trying to change the default colours, sigh.
But our biggest problem is that we were never meant to be here, 14 years later, trying to work around all these problems, ***** about the limitations. We were supposed to by the game, play a few times, and then move on to buying the next game. With all its problems though, it still is the most unique and fascinating game I've ever encountered (not that I have much comparison personally). So here we are, a dedicated, albeit rather small, group of people trying to come up with new ways of enjoying the game