Right now ancient seeds don't have much use. They are used to summon the Elder and that's it, yet they are one of the more common rare boss items, dropping from tougher greydwarves and from spawners.
What if ancient seeds could be planted to grow a greydwarf? Plant one in some cultivated soil and come back when a small twisted root pokes out of the ground. Pull it and your own greydwarf minion pops out of the ground!
There would be a 60% chance for a greydwarf, 20% chance for a greyling, 10% for a shaman and 10% for a brute.
The intention isn't for a single greydwarf to be more powerful than a wolf however, not by a long shot. I think greydwarves would be better as your own horde of minions. Since ancient seeds are still quite rare, maybe planting one would create a spawner that you feed wood and greydwarf eyes to spawn some?