I loved facing in unreal, and it pains me to say this, but this will not work for TF2 as it is now.
2 reasons:
1st, the current map is floating.
While I understand that is intentional, and there is no way to cap it in, you have basically put your map in a box, which is HORRIBLE for optimization as it requires the engine to render the entire map at once. This will result in significant drops in framerates once you add details/large groups of people play the map.
2nd, Class Balance.
This is not UT where all the weapons are at least somewhat effective at long range, while the snipers will love it, heavies and pyros will have trouble staying alive.
Things that might help problem 1:
1. Encase the fortresses to make them less open, applying area portals to the windows.
2. Pull in the sky so it gets closer to the map, perhaps removing the bottom of the island entirely.
Things that might help problem 2:
Cover... add things to the bridge primarily. A TF2 style truck would add a little TF2 style and quirkiness, but if you wish to stay with the futuristic style of the original map maybe some well designed metallic arch tunnels (perhaps with slots on top for demo/ rocket spam?)
Another thing, someone else already made a tf2 version of this map, you might want to check out his to make sure you arent stealing the name... his might have been named "ctf_facing" though