Hi- I don’t know if this topic has been discussed before.
I want to make a suggestion followed by a discussion.
The Spell has it!
The Units have it!
“upgrades” in the INVENTORY.
Then why not the towers/obstacles? Why do we need to place the tower/obstacle (lowering the defence) to upgrade the same? They should be upgraded in the inventory itself.
The devs. can make the upgrade depending on the workers available, in this way, I don’t have to bring a weak tower/obstacle out into the gameplay and upgrade it. It can be upgraded, and used when a specific boost is on the way. Also, since most of the upgrades at higher levels are expensive, you don’t expect a player to bring out his bomb tower (example) and upgrade it. He can do that in his inventory and then use it when a boost is provided.