Ok, I did some test runs. Good news and bad news:
First, the situation. I originally was going to choose the NA Duel server because it is always on arena, believing the center part of the arena where you run through the circle would be perfect. However, it turned out there was a couple of small hills outside of the circle that slowed down the character so had to scrap that.
Therefore, I chose the EU duel server which is on the Ruins map, and found a flat area that had easy markings.
The route:
Starting slightly uphill behind the "rocks" and running in between the tree trunk and rocks straight towards the animal bones. The downhill part was the acceleration room and I did not start the stopwatch until I passed the tree trunk so I would be at top speed. (It turns out a character with 0 athletics still needs a little bit of acceleration time even while completely naked).
Now, this route was flat after top speed was hit, and the stopwatch was hit as soon as the animal bones were touched. This way acceleration was taken out of the picture and it was pure top speed.
I ran 10 times each at an athletics of 0, 5, and 9. Dropped the highest and lowest to account for human error, and averaged them.
The average of the 0 athletics character was: 19.03
The average of the 5 athletics character was: 15.80
The average of the 9 athletics character was: 13.65
So the good news is, athletics still effects top speed (at least while naked). However two things of note. It is definately nerfed. The speed difference between 5 and 9 athletics is only about 15%, where before it would be 25%. Also, this is naked. The speed difference goes down exponentially with weight. Wearing even light armor, I bet there would be barely any difference. Wearing medium armor, none.
Before, it was already bad enough that armor effected athletics so harshly. Now, unless you plan on running around naked with a practice knife, you likely wont be any faster than the next guy.
I would still like to see the differences between equipping different weapons. Still...9 athletics is certainly not as blazingly fast as it used to be.. oh how I miss those days.