Here's an example.
In both the 2 hexes, I have 3 units:
In the left hex, I have 2 rifle corps and a mountain division.
In the right hex, I have 2 rifle corps and a mechanized corps:
Suppose I do an attack with the 3 units in the left side hex. Each of the units will lose 6 MP, so the 2 corps have 1 left and the mountain division has 5 left. Let's suppose that 5 is barely enough MP for the mountain division to move to the right side hex. Suppose that what I want to do is to move the mountain division back to that right side hex, and move the mechanized corps from the right side hex to the left side hex, so that the mechanized corps can participate in a second follow-up attack.
The mountain division has enough MP to move from the left hex to the right hex, and the mechanized corps also has enough MP to move from the right side hex to the left side hex.
However, neither of the two units can do the moves that would be allowed for any of them individually.
The mechanized corps can move to the left hex, but only if the mountain division moves from the left hex to the right hex FIRST before the mechanized corps moves.
Meanwhile, the opposite is true for the mechanized corps. It has enough MP to move from the right hex to the left hex, but it can only do the move if the mountain division moves to the right side hex first. Neither of the two units can do their moves, because each requires that the other one move first!
What is needed is some sort of way to allow the units to move simultaneously - in other words, to switch places.
There could be a feature which allows you to select two units that are in neighboring hexes, and to switch their positions. When you select this option, it would subtract the MP required for each of the two moves from each of the two units simultaneously, and then they would switch positions. This would make things much easier in congested parts of the front - which are usually the most important parts of the front, which is why they are congested!
It would work something like this:
a) You select the first unit you want to move.
b) You select "switch places with a neighboring unit" option on the unit's details screen, next to where it displaces other options such as "merge unit" and "motorize unit" and "multi-role," etc.
c) The game then pops up and asks you "which neighboring unit would you like to switch places with?" It then generates a list of all the neighboring units for which you have enough MP to move from the first unit's hex into the second unit's hex, and which the 2nd unit also has enough MP to move into the first unit's hex.
d) You select the unit you want to switch with, hit an OK button to confirm, and then it does the switch.
BOOM. Nice Quality of Life improvement in the UI, making it a lot easier to deal with moving units around in places like Leningrad where things can get pretty darn congested!
