Please let me know if this has been suggested/ruled out previously.
Current Issue: All clashers have 2 major issues while searching for war - Firstly, it is time consuming, with a lot of players reporting search times of an hour. Secondly, the matches are not even. It has been argued that with the current format, improving one of the 2 issues compromises with the other even further.
Suggestion: I suggest a registration period for clan wars. Supercell can define times when clan wars can begin (yes, they won't begin at any given time). Times can be defined as 6 intervals in a day, say 01:00, 05:00, 09:00, 13:00, 17:00, 21:00 GMT. There is a "register" button for clan war for leaders all the time in clan war screen, not just after the clan war is over, the button is activated only if current war of clan (if any) ends by or exactly at the time the next batch of wars is to begin. Registration opens 4 hour in advance, i.e. when previous batch has started their wars, and ends 15min prior. (Assuming Supercell system requires 15mins to calculate weights of all clans and match clans, else it can go upto 30mins)
Why should this help?: Instead of trying to find a perfect match within an hour, supercell gets a much bigger batch of clans that registered in last 4 hours. This should help in better matchmaking. This will also reduce wait times. For a clan that likes its wars to begin at 9:00, would register for war every time between 5:00 and 8:45, and will get a fresh war at 9:00. zero wait time for such clans!




