Why the Runic Echoes nerf?

Honestly, I'm a tad confused by the MS reduction to Runic Echoes today on the PBE. Really, the item itself has not been very oppressive since its release. Elise was quite strong when it surfaced, but she was nerfed pretty accordingly. Nidalee is pretty strong at the moment, but this item's MS isn't the main cause for that. Her leaps make up for the majority of her mobility as is. The only other champions I see consistently getting the item are Ekko and Gragas, and their performance is in a pretty balanced state right now.

The only reason I can see for the nerf is the oppressively high 58% win rate Udyr has gained with help from this item. But see, this item alone isn't going to make or break Udyr. 3% MS off of nearly 600 MS later in the game isn't going to stop Udyr from running rampant over the map. The champion himself needs to be looked at.