How is this map asymmetrical?

Needs testing.

The bumps in the middle are a cool idea but in practice they may just make pathfinding unpredictable.

Mostly, the difficulty is in predicting which route a unit will take when you give the ordered destination. With the intense raider fights that break out early due to KotH reclaim mode, it can have a big effect on battle outcomes. A raider deciding to take a more efficient but unintended route might walk into the range of opposing forces etc., and that can be game breaking when the stakes are so high.

Either that or there's unpathable hills for hover that aren't obvious.

The map is interesting though. It felt a bit different to other maps on ladder and that's a good thing.