I only read the first 70 posts or so, will read the rest later.
The thing is, cav has inherently VERY good qualities. I think cav would be very hard to balance. I think other classes need to be able to do better against cav without a pike somehow, like making it harder to bump people or something like that. I think slowing down while bumping is a huge nerf and should be treated carefully.
Said before, but in the beginning, cav can choose their battles. They can lance a guy and quickly turn away, out of reach.
When there are more than 1 cav, you can't rely on the sound, at all. Cav sounds louder on your sides, and are pretty silent behind you, from my experience. You could be hearing a friendly cav on the other side of the field, then get lanced from behind. This also creates confusion when there are a bunch of friendly and enemy cav around.
I also see a lot of pikes not doing their job right. I learned that it's easier for pikes to simply protect and stay close to the teammates than just look for/kill cav. Prevent cav from getting close. It's definitely hard to do, since the people you're protected many times make unwise decisions. That's why pikes/shielders should be more in front to protect everyone from the cav and ranged.
Also, even if you have a pike, it's hard to keep track of everything, and even you could get backstabbed by a cav even if you were doing 360s the entire round keeping a watch for them.
A lot of pikers do play correctly, but not enough, so cav players can still do very well.