*muses* Well, as the archers approaches the slit perhaps the object could be swapped for an object using the same model and skin, however it cannot turn and can only fire in a certain angle - say 4 degrees scope. When the archer is told to leave the object again is swapped for the original, freer archer object. Experience would have to be transferred - ie. this is not worth it!
Yup. Not to mention DoF is only meant to be played as a two-layer game - ground and walls. You'd have to do something like reduce the tower transparency and make it not clickable when you hover over it so that you can actually see and move your archers. And in an RTS of this scale, you don't have time to assign each archer to a slit.
Players can, fairly easily, make a lot of modifications to our product with our tools, but this will have to be created by the fans. Precoding unique functions for model modifications is just out of the question. The only game I know of that came anywhere close to this was Spore with its pre-animations, but even they didn't accomplish much more than legs can walk and move any objects, hands can attack wherever they are placed, etc. - and this took them eight years, with some of the best designers in the industry including the legendary Will Wright and over 20 million dollars.