Note: These changes are not absolute, as they are based from feedback not generated by any matches, scrims, etc. However, I think that this version is probably superior to A3 in most ways.
Changelog:
-Fixed holes in blocks with skybox brushes on them (rendering between areas is still a problem, will fix eventually)
-Redid the tiny shack thing in valley to be a raised platform favoring attackers (ie, ramp up to it favors attackers). It makes jumping through the valley more open and gives attackers more mobility through valley while still cutting off weird sightlines.
-Added a building and fence to the valley cliff to make double-jumping as soldier through the valley more viable
-Added decorative buildings to make jumping better and to obscure mid a bit more from those jumping at second
-Made the larger door between the mid/second house and mid much taller
-Added cover to the nearby upper smaller door to block a weird sightline
-Adjusted brushes on the mid structure to further block weird sightlines
-Redid the "trash" area at second (the vans and the pile of dirt) to possibly be more useful. It has high ground about equal to the defender's high ground and has a wall that makes it less useful for defenders. This new design also removes the ability to skill jump on top of the tiny small health building from that area.
-Made the wall closest to the house entrance to second taller to block yet another weird sight line
-Adjusted the door between the the defender's high ground on second and last lobby to be taller, and shifted the second "inner" doorway to the room across from it, to make traveling through this path more forgiving while still blocking a weird sight line
-Adjusted some cover in last lobby to cover a weird sight line from second high ground to last point
-Downgraded the packs near the small computers at last since they're close to the medium packs at the spiral staircase room
-Spiral staircases have been temporarily replaced with diagonal ramps until I figure out how to properly clip the stairs (a copy of the stairs of hidden somewhere on the map, kindof an easter egg)
-Made the balcony at last wider, slightly taller, and just better in general (it also now blocks, get ready...another weird sight line...for the most part)
-Made it possible to stand on the inner lip of the topmost ring of the last point structure
-Added a crate to the stack of crates behind last point to make it possible for all classes to climb up from that way
-Possibly more that I don't remember.
Thank Twiggy and Cabbage_ at tf.tv for suggesting a good number of these changes. Though A3 wasn't actually tested in a match, I think this version is probably better for testing.
Screenshots: