From what I have been told this is coming very close to release, there are not many things that I've noticed that would really make a huge difference in gameplay but here's a list of a bunch of nit-picky things that slightly bother me.
http://puu.sh/oWSAZ/57e94504b4.jpg
These windows are different than the ones on Blu side. Also they're only on the outside. They also look pretty out of place since they're meant to be vertical windows with the little lip at the bottom. If possible I would make them look like how they do on Blu sides outside portion.
http://puu.sh/oWSPt/8a9ab7ea4a.jpg
Windows only on one side. (Same on both sides of the map)
http://puu.sh/oWSXm/eab4638d1c.jpg
This area seems kinda strange looking without a 3d skybox (Not sure if the map had one before but seeing into the void from a common perch spot is kinda weird. You could easily fix it up with some displacements or a few the rock props like you did near the forward spawn). Also I would consider clipping the concrete things so they're flush with the roof and then nodraw most of the inside of that little area under the slope. Better yet just fill it up and prevent stuff from rendering/drawing light all together.
http://puu.sh/oWT9s/68b15e71d7.jpg
I agree with bear and think that this little ledge under the window should be returned. If you removed it for clipping purposes I believe you could just make another slanted brush to surround it and prevent it from interfering with jumps.
http://puu.sh/oWTlh/f76fe20481.jpg
Fence props on both sides going through the roof.
http://puu.sh/oWTnG/db6a3178a8.jpg
Prop clipping into the fence as well as having pretty bad clipping. Easy to get stuck against it and I can imagine it messing up medics surfs since it's common to get bombed while your team is pushing through the lower area.
http://puu.sh/oWTxK/d691a5d17e.jpg
Clipping is kinda weird here but there is not much you can do besides blockbullet clip everything manually with nonsolid props. I would probably clip over the area underneath the stairs since there is no real purpose to ever go there.
http://puu.sh/oWTQ7/f7ab1628fc.jpg
This clipping could be touched up a bit
http://puu.sh/oWTUr/664573af17.jpg
Seems strange to have two different clipping styles directly next to each other
http://puu.sh/oWU3C/e4a5864519.jpg
You can get caught on this overhang. The little diagonal brush probably also should not be solid (Similar to the tunnel on Product)
http://puu.sh/oWUi7/280f21155c.jpg
I'm quite sure this is unintentional.
http://puu.sh/oWUwi/f9c7221c86.jpg
Clipping in this area is kinda strange, could probably be used as a shitty hiding spot but I think you should either throw a prop or two in there and clip the whole area over or extend the little ramp deck area and then add props and clip it over so its a bit more lined up with the wall it is next to. You could probably do the same thing with the area under the stairs since you seem to have done that on most of the staircases on the map so far but having a few hiding spots is fine imo.
edit found more stuff
http://puu.sh/oXj2Q/bc3b261c49.jpg
Pipe between the two things up top is only rendered when you're on mid
http://puu.sh/oXjaZ/83db6f0550.jpg
same thing here.