Absolute skills

I'm planning to get the ultimate skill in the Dungeon campaign... maybe it will work out. I think these ultimate skills seem unbalanced. The Sylvan and Necropolis ultimates are just too strong! The Dungeon ultimate is also cool if you develop the summoning skill well, as is the Academy ultimate. But the Haven ultimate seems completely useless – it triples the damage from Watchtower. I honestly haven't even seen how this Watchtower works, but it seems weak. Also, Dungeon has to develop many not very useful skills if it wants to get the ultimate... is it worth it?