Have a similar idea to yours I wanted to suggest also but slighty down a different line for different reason. Each map has its own advantages and disadvantages on both ends. I think battles should be split into 2 rounds one where you start oneside then in round 2 start the otherside, this is for all game modes. Leaving inbetween the switch would be just like leaving a battle and you won't get any crystals. I have seen battles where players stayed in after the flip and they won on flip. Some battles can be predicted based upon the map.

If I knew smoky 1m was so awesome I would have done it long time ago... smoky FTW!