War, in its 11 iterations so far, is an event that both lasts a very long time, and is a very win-more environment. The worse you do, the worse it becomes and comebacks are extremely difficult if possible at all.
IMO, the first part is not the right one to fix. We can't just make war a monthlong event, it would remove the whole war aspect of it. What I think could be worked around is a help for lower teams to come back up.
Ideas to go around that?
1- Vault is split in two. You start with half your vault, and get your other half in round X ( let's say 4). So you first play 3 rounds, you can see what goes wrong, and try to fix it in your vault when you add your other half between rounds 3 and 4.
2- After every X rounds ( let's say 5) you get the right to put all your cards back into the market and buy new ones.
3- Have a new soldier role. You are allowed to add 6 cards in your deck that are not in your vault.
Those ideas Can help with initial vault mistakes, can attempt to help get new ideas when teams are down and done for, can try to keep a little hope in the bottom teams later into the event.
P.S. I'm not saying those ideas are perfect, far from it, and probably most people will disagree with them completely, but I think it's a decent base idea that could be worked around.