The best ways to make clash of clans more efficient
#1 A "collect all" for resources. Explanation: When you get on clash instead of going through and clicking on all the coins, dark elixir, and elixir things above the resources, a collect all button would just be more efficient.
#2 A next for revenge. When going through your revenge raids it gets annoying to have to return back to the defensive battles and click into the next revenge available. A next for revenge would not only show the revenges that are available but also make revenge raids more common and efficient.
#3 Set Armies. Just like in the recent update with 3 set bases, 3 set armies would be great as well. With an empty army camp instead of going through trying to remember what your special army comp was, 3 set armies would be more efficient.
#4 Builders with multiple tasks. This is especially important for clearing obstacles. Instead of spending time clearing obstacles, it would be more efficient if you could click on all the obstacles you want cleared and have an open builder switch from obstacle to obstacle while you're doing something else like attacking. Its not fun to wait 10-15 seconds on every obstacle when you have a whole base full of obstacles for example.
#5 Lastly, it would be nice if you could have private chats for the leader and co-leaders. They are running the clan and while a lot of clans just make a kik messenger group, if there was a chat on clash of clans for leaders and co-leaders it would be more efficient for running the clan, coordinating attacks in clan wars, and discussing things about the clan.