I have played a couple games on this, and I would say my concerns follow suite with Frozen and Nibs. I actually started pulling your map apart today and toying with some ideas on how to open it up, and force players to use more of the play space. I have a few ideas if you are interested in hearing them. If not this is not a bad map by any means, but i think with a few layout twicks it could be amazing. Send a message if you are interested.
I think it might be my BTB mentality (in both forging and playing) that makes Ark so much fun. In fact it's the most fun I've had on any map without a warthog in a long time. Nibs, the games I've played on here didn't expose any of the problems you bring up. The games moved fast enough that I don't think anyone got a chance to camp that area and it was easily countered from the blue hallway. As you say, simple is rarely good, but I found this was one of the few cases that the simplicity did not detract from gameplay. The clean look kept focus off little aesthetic pieces and on gameplay. Not getting destroyed by power weapons the entire time elevated this above many other maps and really proved the enjoyment inherent in a minimalist approach. All the weapons were balanced in their locations and didn't overpower the other team continuously. Coming from a BTB guy this means a lot. I have only one problem with Ark. There's a bump you need to fix flamingo.
I played the game with Nibs, along with Longshot and we all agreed on a few fixes. I, or Nibs, could show you sometime and see if you like and of the ideas.
That'd be great. I'm looking forward to the next time I catch one of you on. Pyro, you've created quite the hole in my stomach with that.
I think I'm the only person who would ever notice that and it just goes to show how clean the rest of the map is. I still can't get over how awesome the 4x1 wall looks when it catches the light.