Ok, here's my list of things that I think would improve the flow of your map. Generally it's pretty good, but there's a few things that players do because I've seen it, and done it myself.
The first thing is when you come straight out of the middle doors of spawn:
Obviously the initial reaction is that you can't get through that door, so you have to go either left or right. And since there's no indication that there's a bottom path that leads out, players almost always miss it. I know from memory I missed it months ago when I played this map, and then I missed it again playing a few days ago. Just put some indication that there's a out path down below there.
This second flow issue is related to the first, so take a look at both screenshots.
Because you can't go straight coming out of spawn, like I said, you realize you have to go either left or right, so you take a look at what's available, and there's clearly no doorway to the left, so you assume there's one on the right, but there's not.
Even coming out of the spawn on the right door does this too you. If you have an indicator arrow pointing to the lowerpath, this problem is alleviated. The problem is that no matter how many times I look at this little room, I imagine there's a doorway there...I noticed a few people doing the same thing, even if people eventually learn, you have to hold hands in this regard. I'd find some way of indicating there really is no door here, try making the walls out of glass, or just remove it completely.
Coming out of the left door, again you miss the flow if you're not already familiar with the map. You can take the stairs to the left through the doorway there, but because there's some stairs directly infront of you, I always assume there's a way out up ahead if I take them. Again, an indicator arrow will help.
And to finish up, coming from the opposite direction, go ahead and place some indicator arrows here, it could only help the flow:
This area between points 1 and 2 is tricky, either you have to take the main path, or track back and take the upper wooden path on the right, which is really a headache sometimes, especially if a team is already taking point from you, and you're forced to take the main path. Because you only have 1 path to the point it becomes a deathtrap as you're fighting uphill to it. My suggestion is to add this set of ramps/stairs to the drop off area on the left:
This will give more access to the point for a total of 3 routes, which I think you should have.
Here, it's almost a mean trick. Sure, you can jump on that rock to get up if you need to, but it isn't even close to being the right shape or having the right position to be able to climb on. Either lower it for players to jump on, or raise it so it's clear you can't without first boosting on something.
In general I think the sightlines on this map are ok, but there are a few places I'd change--here for instance, since it's a doorway to the whole area, it becomes unpleasant to walk around a corner and be shot on sight. If you obstacle in front of the doorway it protects on both ends.
And same thing here:
Lastly, this was the forward spawn that got me a few times.
Clearly there was an arrow there telling me which way to go, but if you beat me over the head with the fact, it would help me a bunch. Namely, repositioning the arrow here, and making it parented to a func_door so when the spawn isn't being used it'll pop down out of sight. And by placing it at an angle pointing forward, you're actually blocking me from traveling right, thereby serving 2 kinds of directional reinforcement.
Hope that helps!