Kesh, you have no proof that this was ever changed. Unless a dev somewhere said "Athletics was nerfed" then I seriously doubt they put extra effort into programming a ninja nerf.
On my study, I showed the difference in speed between 8 and 9 athletics while naked running on flat ground.
When naked, as in, 0 weight, there is no acceleration time, you hit top speed instantly. Even with extremely light armor such as a robe and a light weapon, you hit top speed nearly instantly.
The difference between the athletics while naked is purely based on top speed.
The reason why athletics doesn't "feel" as fast as it used to is because everyone is wearing medium armor where it doesn't make that much of a difference. There were more peasants and tin cans back then so you could feel the difference in speed. (Peasants with low athletics skill and tin cans who are slow anyway).
If you truly think you can keep up with Mayor when it is not raining (read above, raining decreases move speed), then go ahead and try.
I know I've raced Mayor in clear weather with my 9 athletics vs. his 13 athletics both wearing very light gear and not only did I obviously lose but he consistently pulled further away. (He didn't realize I was racing him most likely because I was far behind him trying to keep up).
There are many factors people don't realize that slow a character down that I've just started to dabble in.
For instance, holding a Steel Pick makes you move substantially slower (yes top speed) than holding a Side sword, even though the weight difference is only 1. Why is this? I don't know. Its the same thing with a pike, you can have a pike and a similar weight polearm, switch to the pike, and you are moving slower. As soon as you switch to the other one, you move faster. Even if the weights are the same.
To clarify:
People who wear medium or greater armor don't notice the differences because they are too small. But those of us that have always played Light armor or less high Athletics characters can see the minute differences between changing gear, or shields, or weapons.
I've even noticed a difference carrying around a 1h sword (Side sword) + Buckler, with a total weight of 3.8 vs. an Iron Staff with a total weight of 2.0; Guess which was slower? The iron staff.