This is a good change. However it needs tweaked cause there's a couple drawbacks. First, when everyone is kicked out, many are just quitting for the night instead of continuing to fly which cuts back on the numbers. Second, when you go to get in, there is a delay in startup so the off peak arena doesn't appear right away. The one drawback I could see in when I heard about this new method right away is that there may be a really good fight somewhere and one of the countries may be on the verge of winning a long hard fought base only to have to quit. I know things stay as is on the map, but the same people are not there to continue the fight at 3 or 4pm when things change again. So you're killing momentum and enjoyment.
But anyway, HTC, what you should do is one of two things.
1. Leave the Orange up and close Blue then use Orange as your one off peak arena.
OR...
2. Open the off peak arena before closing the others to allow a smoother transition.
I would say Option 1 is best. There's no reason for a whole new added arena (off peak). Just leave one of the prime two open and change the numbers allowed in. This would allow for a continuation of gameplay on the same map and also just have 1 arena. It would allow for anyone no matter where they live to get on anytime and continue an ongoing battle.