Refund for troops that survive attacks. And using elixir to search for opponents.
I think a small refund of 25% for the total amount of troops that survive attacks would be nice.
Instead of using all or most of the elixir you've obtained to make another army I think at least using half of it to make the same army would be nice so the other half can go toward upgrades. The refund would help you keep most your elixir, both dark and normal.
Also, instead of using just gold to find matches elixir should be used to find matches as well and it would be the same amount. It would also be nice to have a choice to which resource you'd wanna use. Like walls have both the options of payment to choose from.
I like the refund idea. 25% is a bit too much, however. Everyone would train all dragons and destroy bases with that, with little losses. Perhaps this can be a clan perk!