Well I thought you would join the match queue already knowing what the expected wait time would be.
And on top of that, there would absolutely be a 5-10 minute window before the actual war starts, just like there is now.
Matchmaking is nice. I would not want to wait 24 hours for a war, though :p
Like big games do (those that have matchmaking), where the waiting time to match you against someone with your approximate skill expands or contracts depending on how many are in the waiting queue would be nice. I.e. If 50 gangs are in the waiting queue, the approximate waiting time for your gang might be 5 minutes. If 500 gangs are in the waiting queue, it would be closer to 5 seconds.
So an instant war would be best, in my opinion, but overall, good post. +1.
I commented about this on another topic but I couldnt really explain my idea well but your idea is somewhat similar to what I was thinking. I like it more fair wars