Just to clarify.
All the resources in your bank did not change. Your losses from the old system still apply toward rewards in the new system.
When you fail a position, but you were close to completing it, 30% of your army will survive and come back. You can't abuse this. That 30% did not engage in combat at all. That means they did not inflict any casualties. The battle results are the same as if you had sent only 70% of that army.
For the people who aren't number crunchers, things worked out like this.
Old System
Big loss, big loss, big loss, big loss, big payout
^At this point, you're close to 0% original strength and have 110% of the last payout banked.
New System
Small(er) loss (since you gain a percentage back immediately), small loss, small loss, small loss, small loss, small loss, small loss, small loss, big payout
Before the big payout you're close to ~0-10% original strength and have 110% of the last big payout banked, and it has to be actually banked.
A very important note: the overall rewards are the same. Ahem. The overall rewards are the same. You're just going to be playing a lot longer, which is good when it comes to position tournaments or getting value (e.g. combat experience, enjoyment) from your units.
Another note, agreements benefit you a lot more. Under the old system, you had to lose 110% of your last payout no matter what. It didn't matter how strong they were. Under the new system, you still have to lose 110% of your last big payout to get another, but you can last a very long time without it. With maxed out agreements, good elixirs, and good army compositions, you can earn up to 75% of your army back on each position. A 40% boost to your units means you lose 40% less, but the payout remains the same. Just remember that you need to lose your army several times over to get a big payout.