From HH's map night:
Incredibly pretty map, and just walking around was fun (which shouldn't be underestimated). A few things with regard to gameplay:
BLU seemed to have a very easy time. For a bunch of the caps, the BLU spawn moves up right along side them, so much even that when I spawned and walked to the cart when the team cappedI saw my teammates coming from the spawn and be right there immediately. This seemed to make it incredibly easy for BLU to be at the cart 100% of the time - as opposed to the cart mostly being in RED's hands until BLU pushed through. Now, that may be too little experience with the map, but usually when people don't know maps well enough it's RED that tends to do well, instead.
You mentioned sniper lines: they're mostly fine, because they tend to focus on the area around the cart itself, which should be the most dangerous area to start with, but right at the end they look out directly on (see through) RED spawn doors all the way from very safe battlements. I could line up a shot from the heads of people inside the spawn and then shoot when they came out.
With regards to the railings: they do make for visual clutter, for sure, and they definitely don't need to be everywhere. At least make it so there's designated drop-down holes in the railings or remove them entirely in places where you want people to drop down (and for visuals sake make them into hazard strips or something similar). Railings tend to make explosives and sniper shots kind of awkward. No need to remove them all though, just around areas that aren't battlements or connection spots.
Tubes are fun.