You may not get the troops back but you CAN GET THE FARM SPACES BACK. Just ask for too many shipments and as mentioned the villagers will start killing your troops when the mood drops too low.
Someone already found a strategy to overcome the population problem.
I hate farming in this game. It’s tedious, boring and ridicules. Possibly because I am lazy, but it doesn’t matter, I stopped enjoying the game and left. And so did a lot of other players.
You can't spend a day at the office, just to come home to spend the rest of your life farming.
If you loose out on population because of stationed troop so what? You will build quicker because you have more resources. You also have an alliance to help you out when you are in the crap.
You can also setup attacking cities on the frontline with higher number of active fighting troops and feed them from the back with defensive cities who's secondary purpose can be to act as supply lines. Typically lots of players have more defensive cities than offensive – depending on their situation in the game.
I definately favor this change and the others, looking forward to it.