Taking a quick look through your map. I'll just be making some notes as I go.
1) Spawn. The size and shape seems fine for a badlands style last. But I feel like you spawn WAY too close to the door and that the ressupply cabinet is way too close as well. For this style spawn players should spawn some distance from the door and resupply should involve you having to actually walk some distance into spawn. Otherwise, heavy can just chill at the door and strafe left to get 250+ health back in an instant. Likewise, a soldier can run gunboats and bounce himself out the door and be halfway to second before the round even starts.
2) The last point is in a slightly recessed area (8 units or so). You should avoid those sorts of recessions and dips. The lips of that area will catch rockets and make spam going into and out of that area incredibly hard to predict. You'll think your slamming a rocket into someone for 100 damage but all the splash will get caught by the lip. The same is true for the hazard triangle brushes, and those will actually clip people if they try to jump while next to it (they'll jump straight up instead of going forward or backward). Especially for alphas you should focus on extremely flat combat spaces and such, instead of having a bunch of smaller recesses.
3) Only two exits onto last? Seems Like a pretty bad idea. As your going for a badlands style last, check the number of exits for that map (4) and maybe come up with something similar. You have that area on the right side (for defense) that seems perfectly reasonable for another path in.
4) The glass windows pushing into last are going to screw you in terms of optimization and the sight line to second. ALso, makes pushing and defending last pretty annoying. They can see everything your planning to do without any real penalty. Instead of some uncertainty in terms of how combat will play out at last, the attacking team knows everything well ahead of time. By comparison, the badlands upper area with the window is much smaller and you can be attacked from both right and left, meaning that if you want to use the window to peak, you have to put yourself in harms way.
5) Second seems okay. Sniper sightlines are defintely a worry, that balcony will be pretty powerful for shutting down pushes. The water drop down thing: not sure thats a good idea. The three maps that i can think of with it (freight, well, and waste) that pathway almost always ends up useless. I would consider making it possible to both enter and exit the water entrance. Again, as with last number of exits from either mid or last is a bit worrying. At least three from both directions is preferable IMO.
6) Mid seems like the coolest area in the whole map. From a 6v6 perspective I could really see that layout working out. However, I don't like the lower area much at all. It doesn't really go anywhere, and the one place that it does go, would actually be easier to reach via traditional means. When I came up the ramp from below I assumed I would be coming to the middle point itself, but I ended up behind it. I think one much easier and simpler version of what your trying to do would be to have the lower entrance go across to the other teams side, so you could push a scout behind to flank, rather than just ending up on your own side of the point.
7) Death pit surf ramp thing beneath the point is very strange. I get punished for getting stuck in some weird lip/culvert thing? Just make a flat intersection between the concrete floor and mid platform.
8) Arrow signs seem a bit odd. Just use a regular square/rectangle brush instead. At this early state in development, the jagged geometry will only confuse people visually.
9) Extend your skybox walls! Do it now, don't use the excuse that its early in development. If you figure out the right distances between in game geometry and where the skybox will be, it will be much easier to work the map at a later point. I'm thinking primarily of the wall to the left of the second point (defending). If you jump up near that wall you can see into the forward ressupply. You might not be able to see players (I wasn't able to check) but its very disconcerting to be able to see that.