I wouldn't remove it, but rather add a building to choose from. Like in Heroes 4.
Either you build undead or knights. And you can choose, and you don't have to kick anyone out. There are two types of knights in the game, and it's not difficult to come up with an alternative upgrade.
Exactly!!! I completely agree! Good idea:)
Added 1 minute ago
Training is limited and expensive, so it doesn't unbalance the game...
in the early stages, everyone has 1 city...
But if you play for a long time, it can unbalance the game. Death Knights would strengthen the Necropolis. Let them even increase by 3 per week instead of 4.
