Hey D A V I 5 -
We do update skins and champions as they get older. We did a ton of texture rebalances last year, Butcher Urgot being one of the affected skins.
As Ququroon mentioned during these rebalances:
*"We're looking to address the fact that many of League's older champion and skins were created using the Rift's current look and color palette (or even older ones), which continues to evolve over time. At this point, many champion and skin textures need a bit of rebalancing to ensure they look nice regardless of where they're standing, or who they're standing next to. We're talking just about every champion and skin released before 2013 (with a few outliers)." *
We aren't reverting these texture updates, as they were intended for the reasons stated above.
As a side note, the terms of use, also known as the fine print that no one really looks at, but agrees to, states the following:
"You further acknowledge and agree that Riot Games has the right, but not the obligation, to delete, alter, move, remove, or transfer any and all Game Assets, in whole or in part, at any time and for any reason, with or without notice to you, and with no liability of any kind to you.".
Hope this answers your question. If you have anything else, feel to ask. ^-^