Its the cap, Paragon movement speed is capped at 25% too. Its there to make it so you can cap move speed and mystic away the move speed for a more useful stat.
There are other ways to move even faster, for example the nice bracers that Jaetch linked in his stickied thread. If the cap wasn't at 25% but higher, you could move absolutely insanely fast by adding skills and those legendaries, to a point where the game would break ;-)
MS is almost like the new "required" paragon bonus, similar to MF in paragon 1.0; I don't care too much about the other traits but I really want to get to 200 at some point to be completely independent of MS on gear.
Then, I checked my MS in the details screen and to my surprise, it raised from 24% to 25%.
Is this because of the 25% cap?, or the boost works in a different way?.
If it is because of the cap.. fuck that cap, I want to move faster.
MS is almost like the new "required" paragon bonus, similar to MF in paragon 1.0; I don't care too much about the other traits but I really want to get to 200 at some point to be completely independent of MS on gear.
Edit: Or these boots -http://www.diablofans.com/forums/diablo-iii-general-forums/diablo-iii-general-discussion/81021-show-off-your-loot-2-0-legendaries?comment=24