Currently, all alliances have the same starting time. For those in eastern US time zone (presumably a large share of the total population in game), the start time for the first war was 4 am.
This is unfair because leaders/generals from that and nearby time zone cannot be reasonably expected to start war promptly after 4 am. Each single war lasts 24 hours regardless. Hence the starting time will probably be progressively later. At the end, it becomes almost impossible for the alliance to start a war in the last day. In comparison, for those in western and central Europe, the start time works perfectly well.
In the first war my alliance had, only 2 out of the 4 surviving alliances were able to start the last war. And that is unfair.
My suggestion is to have multiple start times and let alliances choose which one to join.