I couldn’t find anything on this searching the thread but believe it could enhance the game as well turn a profit. I’d recommend the ability upgrade atleast two troops or spells at one time as long is one was dark elixir and the other would be just exiler. For a profit you could allow to purchase a second research lab for like 1200 gems. It would enhance game play for people who have been playing forever and make it only available at either TH 9 or TH 10.