New Idea for TH upgrades: Traits
Something that might entice newer players as a fun update:
Mmo style upgrade for each TH. You get to pick one of the three traits for each new TH that you upgrade. The added abilities stay with you for that TH level, and next TH it resets and you can choose again :
Warrior: Emphasis on defense, you get one extra defensive turret. IT excluded
Hunter: Emphasis on attack, you get 10 extra camp space.
Warlock: Emphasis on spellcasting, you get one extra spell in your factory.