Tested this on HonC the other day, here's some constructive criticism and little things I noticed.
There seems to be a lot of "junk" on the map that could probably get refined. There are a lot of FPS issues that seemed to be plaguing everyone on the server, and reducing the amounts of stuff you have on the map would be step one to help this. The other issue with all this stuff is that it seems like everywhere you go you are colliding with something. A lot of clipping should get done on the map to smooth this stuff out, but I also felt like I was constantly fighting the map itself to get to where I wanted to go. IMO, go through each stage, look at every prop and say "does this specific prop NEED to be here to sell the detailing, or improve gameplay?" if not, axe it. Time to make the hard cuts.
Stage one is probably the most refined stage, and I'd bet it's because it's been played the most by far. One of the inherent problems with multistage is the later stages just getting played far less. Did you split the map up during development to test each stage out individually? I feel like there are some strange flanks that give attackers a big advantage (probably not a bad thing for a stage one, really), but I like the spawn location in relation to the final capture. Far enough away without feeling impossible to save.
Stage two is probably the "messiest" stage with stuff in it, I felt like I was constantly having to jump over and around stuff to get to where I wanted to be. The last is a crazy choke point that always feels like we basically have to spawn camp our way to victory nearly every time. The rest of the stage isn't bad, it just goes from being pretty open with breathing room, to small doorways leading to cramped gameplay space.
Stage three is hard to get to, and feels like a big box with another raised up box in the center. The outside areas are barely utilized because they are so far out of the way, and the center ended up being the only area fought in. It feels a bit overscaled. Combat happens at pretty long distances at times. Being this late in development this doesn't help much, but thought I'd mention it anyway. I've only managed to play this stage like twice during this maps development, so take my opinions here with a grain of salt.
Some specific spots of things I happened to grab screenshots of:
Super dark and weird spot. Really easy to ambush from here. I'd probably seal it off with some detailing of some sort, personally.
In the heat of battle, trying to run in to grab health, I kept wanting to turn towards these to get it when seeing them from the side. I'd just make one of them a cabinet, myself.
Had some FPS issues around here (My normal is 200-250 capped, if I dip below 100 I usually know an area is in need of fixing up.)
Could clip these, or just remove them.
More FPS issues around here.
And here, when more people were around.
Hope this helps. You've got a lot of map here, so good job getting it to this stage in development!