Regarding just the center cap point, I love a mid that is also suitable for MGE 1v1 soldier vs soldier battles, but without the great heights like the cargo boxes on granary. For example viaduct you can really maneuver around the middle rocks, peak from side to side, jump onto the rocks, peak over the rock, it gives you safety and yet you are so close to the action. Same with the boxes on the sides of the cap, you can single jump onto them. This makes playing a class like Heavy much more interesting when you can jump on things, shoot over things, and immediately fall back or push forward. Those low, jumpable obstacles make for a great part of mid.
Watch from 2:00 to 3:00 to see what I mean
http://www.youtube.com/watch?v=kP-6tvuCuhk