A few thoughts on beta 4 from a solo runthrough.
I appreciate it is early but I should comment that I don't like the spawn room having that door overlay at the back in the middle or the lights on a beam. Just a few personal things worth mentioning just in case they get lost in the details later one.
Room after spawn: This seems rather pointless having an enclosed room here and servers no purpose that I can see. Going outside to the left (blu pov) to the "intelligence" side of things has a room that is far too close to the door. This room shows an "S" connecting room which doesn't do much. It should be combined with the room afterwards similar to that in Turbine giving it a purpose.
Outside near the intel itself, the ramp that leads up here forces you around to the right, that room behind the intel should be pushed back into the corner giving a path around it. On the other side there is a ramp going back down with another (I assume it will be a displacement) that I feel should force you to use the ramp rather than have a similar incline.
The intel location itself feels odd to me, a bit in the middle of nowhere and no features to point it out. I would take that room behind (as I suggested, move it back) and make is a "broken" down older building with the intel in the corner so it feels more natural.
Heading towards the water now from left side (which looks great), there are a few rooms here that feel a little pointless. You walk through them and I can't see anyone using them for much at all. A simple overpass would be more suited or somehow combine this with the middle section more.
The sniper point in the middle either side of the bridge is a nice feature but I feel it could use a few things to block the line of sight to the middle of the map a bit.
Back to the intel taking the right path this time, there are three rooms you pass here, each with absolutely no point that I can see. It then leads into a door that looks completely out of place, more suited to Yukon than a CTF map. Left of this is a room with two ramps and a computer in the middle. I feel these ramps are far too steep currently.
The room before that with the two stairs (lower point in the water to get to the far right) has a room that goes up two levels with ramps. These are tucked away too much so something like the last CP in Badwater would be better (I might need a screenshot if you can't find that).
The last thing is the bridge in the middle of the map. I quite like this but it really needs another access point directly to it as suggested earlier. Also, when backtracking, you go up two ramps (to the sniper deck) which are a bit difficult to navigate and should be spread out a bit more.
Feel free to take anything into account and ignore other parts as needed, these are just a few personal opinions so may not be useful. Also, if you can't follow I can try to explain with images as required. Still, a nice map idea if a bit complicated and large (between intel and middle point).