First of all, your work is GORGEOUS.
Second of all I've never seen a map thought this way in TF2 and it's both refreshing and interesting. I hope that the following feedback will be useful to you.
General design issues
Ok, usually TF2 maps feature a fair share of signs and arrows to highlight ways players can go. So most of your chokepoints could use some.
Then, the size of your doorways is too small in my opinion. TF2 players cant strafe jump past choke at insane speeds like quake, and as such they need much more room to somewhat avoid spam.
http://puu.sh/wCrRD/965ff13210.jpg
This doorframe offers no wiggle room at all. You should make much bigger, like the size of the wooden platform, and then use this size everywhere else on the map. It's no fun for most players to move through tiny doors that limit the dodging they can do.
http://puu.sh/wCrWW/42abd57a73.jpg
Here for example you reduce the size of stairs by putting thick walls. I think that the thick walls aren't needed and that you should remove them to make the stairs wider. Currently i'm sure that I can fire rockets right at the middle of the stairs and splash the whole width.
http://puu.sh/wCrWW/42abd57a73.jpg
Same story here, it's too narrow.
Last
http://puu.sh/wCu2l/457953bc23.jpg
I suggest you add a way to jump up to the upper floor from the mann co crate. Why isnt this room replicated on the other side? You may as well carry this symmetrical concept to the limit :)
http://puu.sh/wCu7w/c51dd3d39f.jpg
Make this wider, blah blah blah
http://puu.sh/wCubB/fa9ecbe3e7.jpg
Potential sightline issue there (the same on the other side). It clearly helps defenders more than attackers. I suggest moving the big pillar to the right to make 2 staircases of the same width in order to narrow the sightline. Also why not keep the symmetry between pillars/staircases?
http://puu.sh/wCuiq/9985399f3f.jpg
I don't think this crate serves any purpose. It does not even block this sightline :
http://puu.sh/wCuko/9355c68e0d.jpg
You should remove it IMO.
Second
http://puu.sh/wCuko/9355c68e0d.jpg
Very big sightline. Maybe make the pillar thicker to narrow it?
incoherency : i can jump there :
http://i.imgur.com/1rvnRom.jpg
but not on there:
http://i.imgur.com/54IH63b.jpg
You should remove these wooden bits.
http://i.imgur.com/rQxQ0VS.png
Sightline issue : i can snipe attackers from there and they can barely see me. I think you can remove the wood crate. At least attackers will properly see the sniper when they peek.
http://i.imgur.com/2FQCD0g.jpg
And if you need to deal with the sightline you can always reshape this pillar to put in more on the left.
http://i.imgur.com/xidy3ow.jpg
This roof makes it hard for attackers to jump through. Can you scrap it to give the room a higher ceiling? It'll make the choke much more fluid to go through.
http://i.imgur.com/zfgMf0U.jpg
I dont see what purpose these stairs have. To me they just make spam and sticky traps more effective. I think you should keep the door height and remove the stairs to provide a fluider choke.
http://i.imgur.com/n8PEO89.jpg
Unintented hiding spot I suppose?
Mid
http://i.imgur.com/K5lSGUW.jpg
A team that wants to push this side must take a veery long trip as the wall is super thick and the stairs are all the way to the right side. Could you reshape it to make the walking distance shorter?
http://i.imgur.com/Cu3RJOY.jpg
Having no door here feels weird (and limits attackers options to rotate around in order to push). I suggest two things :
-make this a glass window -> both teams can see each other -> less frustration about uncalled players backcapping/flanking
-make some sort of doorway like you did on the lower entrance (like with a wall in the middle and 2 side ways) + add a drop down that goes there (and carve doors on the sides for example) :
http://i.imgur.com/Y9y1gkI.jpg
http://i.imgur.com/Ss1WaFc.jpg
This is a super good defensive position for a soldier. making the whole staircase doorway wider / changing the medium healthpack to small should tone down the strength of the spot
http://i.imgur.com/KPYzmIt.jpg
From this spot as sniper I can be effective for free on all the doors. I suggest reshaping the side entrances to add some kind of line of sight blocker/move the pillars to the middle of the chokepoint. Unlike quake tf2 railgun (aka sniper) one shots people and make pushing a ***ing pain.
http://i.imgur.com/rHBYrRD.jpg
Maybe add some corridors that link this room to the left and right ways? It'd provide faster rotation which fluidifies the game.
TLDR : I like wide chokes that allow easy and fluid pushes but I also love your general idea and artwork! I wish that I can craft such things like you one day.