Exchanger, Th11 and new defences
First off, the exchanger. This building should allow players to change gold to elixir, elixir to gold, and elixir to Dark Elixir and gold to Dark Elixer. 1 gold should be equal to 1 elixir and the same the other way round, but for 1 Dark Elixir, you should have to pay 100 gold or elixir. This is because Dark Elixir is a lot harder to obtain. Next, Th11. This should have the appearance of a Lv11 Wall, with bits of blue electricity coming off of it. I should include 50 more walls, another cannon, archery tower and a new defence. This new defence could be called the Mounted Tesler, as it uses electricity, like the tesler, but more powerful. WAY more powerful. It fires a line of electricity, like an inferno tower in a way, but concentrates on a single enemy, dealing a heck load of damage. I'll leave that for you to decide, along with the appearance. I have an idea on what it would look like, but it's hard to explain.