My opinion on the map is basically this:
I love the thought and detail put into the environment, and I wish there was a PVE story mode to compliment it so I would have time to just go through and explore and learn about the different areas. Even if it's just a Winston flashback.
However as a gameplay map, I can't put my finger on it, but it seems too open. This makes it harder on attack mode. You can't easily sneak by, you have to walk too far out into the open to get into the side paths to sneak around as a reaper/tracer/etc. Also it just seems people are too vulnerable to a decent sniper who's defending.
It's not a horrible map by any means, but if they ever implement a downvote option for maps this will be the first one on it.