So I finally got some spare time to adress some of the changes in a3, and additionally provide some of the thoughts behind the changes (to compensate for the missing changelog):
One of the problems in the previous version, was the difficulty of defending last. Blu could quickly and easily arrive at the point and red had little to no effective holds.
I changed a couple of things to fix this:
I blocked out the sneaky route leading from the second point to the staircase just besides the point. Instead, the exit of the route is now relocated under the bridge.
I believe the previous lower route brought you too close to the point and made it way too easily to rush, especially since the spawn was on the same level as the route. The new exit is further away from the point and encourages Blu to utilise the "marsh" besides the point more.
Red has then also an easier time watching the exits.
Furthermore is the red spawn raised, and the defensive structurer has been enhanced with balconies, to better facilitate holds.
The staircase up to the balconies has also been moved closer to red spawn, so it's easier for the defense to control it, and thus also the buildings by last.
The shortcut from last to 2nd in the buildings has also been highlighted better, since it was hardly used before. It's also a straight hallway, meaning it's easier to spot flanking enemies.
Finally, the upper balcony with the crane has been closed of ( I liked it tho

)
The large tower of crates by 2nd has also been removed, and the central walkway has been moved closer to the point to open it up a bit.
This also makes holds on the 3rd floor more viable (and amplify the feel of verticality in the warehouse).
Further changes includes:
Mid
- Extended the capturezone, doors and area around the mid, to make it less spammy.
- Rebuild greenhouse. It's now completely transparent.
- Added two small shacks on either side of the point. Snipers/heavies can utilise these as cover while contesting the point.
- Lovered the flowercases, to improve the visibility of sentries in the building besides mid. You also don't need to crouch jump to climb them anymore.
2nd
- Removed tower of crates to improve visibility, and moved central walkway to reduce spam on the point.
- Straighted out the hall leading to the one-way door
Last
- Expanded the lobby before last.
- Raised the platforms outside of spawns. They're now about 192 units above the water (same height as the point).
- Added a balcony to the upper floor of the buildings besides the point.
- Relocated the staircase going from defenders spawn to the upper floor.
- Highlighted one-way door better.
- Turned the block by the point into a crane-like structure, to increase visibility.
BTW: You're always welcome to include this in any imp any time if you want. I would be very grateful if you did!