Honestly, entropy didn't win because of a well made vault. Entropy did well because there was no such thing as a bad salvage for them. Entropy, as an element, is chock a block full of control. A successful deck for them was one hitter, (preferably quint'd), and enough control to stall for the win. Every deck had discords and other forms of control to slow down the duo nature of their opponents decks, and then a few durable hitters like abominations and pheonixes and dragons to finish the job.
All they needed to get a good salvage was either A) more control, or B) more damage. If they got either of those things in salvage, they could use it.
Other elements, like water, had a far harder time with salvaging, which I personally believe led to their downfall. Water duos extremely well with half the elements in the game, but outside those very specific strategies, water doesn't work well. Another good example of this is earth, or in this war, death. These three teams, because of the difficulty of their salvage, all had major climaxes in their strength, followed by huge crashes, and eventually their loss of the war.
The only "strategy" that allowed entropy to avoid this was how easily their element lends to rainbow.
On that note, strategically, the "climax" theory lends to the following strategy:
1) Win the propaganda
2a) Define the rock-paper-scissors decks (this war, firestall, rainbow rush, and discord). Entropy succeeded in defining two of the three
2b) Use your propaganda/salvage to build the rock-paper-scissors decks. As these decks are the most common, the majority of salvages will assist you in rebuilding/enhancing them.
3) Wait for the elements that failed in step 2 to climax and crash. Without the three "staple" decks being the center of their vault, their salvages will eventually force them to deplete their own vault in the form of suicide.
4) Last as long as you can versus those that succeeded in doing steps 2 and 3.
Another option would be to come up with a deck that defeats all three of the rock-paper-scissors decks, such as a fractal (faster than graboid rush) cockatrice (too tough to stall) with novas (beats discords). I could sit here and argue that deck is undefeated and should have gone undefeated, but the data shows otherwise. Current data shows this option is worse than the aforementioned method.
Entropy and fire did well because they defined the three decks. Life, Fire, and Entropy did well because they adapted to them. Looking at air's final decks, they were a discord deck, a rainbow rush, and another discord deck. They also had two fire stall decks, in the form of a cremation rush with rainbow control, and an unstable gas deck with OEs. They, too, succeeded because they adapted.
This is the main bit of "strategy" I learned from this war.
The only other thing I learned was the golden rule: pendulums, pendulums, pendulums. An off element pillar is a dead card in 10 out of 11 decks. A pendulum can be used in any duo AND in a mono.
