We talked about that and did not implement it this way, as it would cause a ton of other problems.
Some of these are:
- selecing a single allied unit is always a bit tricky. especially if there is another unit close, you might accidently select it, even though you clicked on a different unit. So it will always need a ton of micromanagement, just to get the units in position.
- You could use it for killing units outisde of the fortress in the middle of a fight, just to stop the enemy from getting experience - therefore the range for the spell must be minimal and basically just a few milimeter around the citadel, as we don't want this to be a viable strategy. And having such an ability with such a small range always feels frustrating to use for buildings. (objects that can't move)
- it looks horrible if you can make everything just vanish in the middle of the field.
- the work needs a lot of time, which we rather use on something else.
There are a ton of different points why we haven't used it as such an ability, but as the current system, event hough it has some downsides.