What if the devs put up three magic barriers at the entrances of the bases.
Each can be brought down only by taking down the respective door guardians, so if you destroy the Yellow door guardians you now have access to only that entrance with the same principle being applied to each entrance.
This would prevent players from outright ignoring the door guards and breaking the shrines immediately.
I know some of you are gonna say, "but what about The Doorman and his portal gun!?!"
That's a good question, the barrier would be a one way for enemies; meaning they can leave the base but cannot enter it.
Now if your Doorman decides to teleport Victor into your base, and your teammate can't seal the deal. Then it's on you and your team to fix Doorman's mistake of allowing a wallbreaker Victor into your base.