Just a suggestion. I really love the idea that you must first in the goblin campaing to get the goblin king. I hope they add a final level called the Gobline Palace, filled with storages and a fully upgraded goblin king. Once you beat the Goblin King, he becomes yours (assumign you bribe him with Dark Exlir, Gold, and Regular Exlir).
In gameplay, I want to suggest that he becomes a super goblin, much like the other heros. My idea is that he starts fast, is able to jump over walls, and targets collectors at first. However, on the flip side, the more he collects, the slower he gets, and eventually, after a good amount of loot, he can no longer jump over walls.
As for his speacial abilites, I guess he grants the ability to jump over walls to nearby goblins and...I guess speed? He of course, summons goblins
I wish to keep this the Goblin King, because that just sounds natural. Almost every fantasy book has the leader of the goblins called the Goblin King. Thxs for reading this.
Edit: I just realized that someone else proposed the idea of jumping over walls. To those opposing the idea though, most people mot storages deep within their bases, defended by a ton of defenses. So its not too op.