EPTThe main problem seems to be that terran, which is a slow race, arrives at the enemy base too quickly.
1) The mineral-only expansion could be moved closer to the main/natural. This makes defending it easier.
2) The small ramp leading to the expansion at 9 and 3 o' clock could be removed and space expanded. This would work well together with 1)
3) An alternative to 2) would be to move the 9 and 3 o' clock expansions closer to the main base and to expand the space in front of it, instead of removing the small ramp. This might not work well with 1)
4) Another alternative to 2), the two ramps closest to the highground 3rd base (11 and 7 o' clock) could be merged into one that is as large as the biggest ramps currently are.
The other problem mentioned was that terran can defend its outer bases too easily.
5) The two top right expansions could be connected by land (11 and 12 'o clock, and the same for bottom left) and neutral buildings placed between them to create an alternate route to attack in the mid/late game.
There's also another idea that reduces terran mech effectiveness, which is to reduce space in the main base so that some factories need to be built outside. This doesn't hurt protoss as much with their smaller gateways. Some of my other ideas can be used for that.
