Concerning the audio update patch a while ago

So back a few patches ago, 4.12 I believe, League transitioned to using wwise as a new audio engine. I understand efficiency being the driving reason behind all of it, but since then I've noticed a spike in people that have issues still trying to mod their own clientside audio files, such as spell casting, taunts, etc., as they were able to on the old engine. After this update it appears this kind of clientside customization is no longer possible; my own experiments meet with issues with recompiling custom audio, something I assume has to do with hexadecimal compilation?

I suppose my question here is directed somewhat to Riot in asking if these kinds of modifications are still possible? If so, can someone point me in the right direction?