I was thinking why you cannot continue playing with units you have after your base is destroyed ( especially in team ) , how to justify that. I thought maybe you have player (leader, general... ) in base and with base destruction he dies. And then I had this idea
Leader unit: You can spawn leader unit from your base. You will start with infantry ( on rank private ) and you will unlock stronger units as you level up. This unit will be free, but it will have one catch. If it dies, you lose
. ( and if your base is destroyed but you have leader unit outside, you can keep playing with your units, and even buy new if you have tank factory/airfield ).