So IronStylus was streaming some Riven fanart last Sunday, so I got to ask him a few questions and one of them was about Udyr, "What do you think about his visual state?", and I basically summed up his answer:
"Udyr does look pretty bad (even though the texture rebalance helped him as a bandaid)- Could use love and consistency. His visuals need to represent where is he from and where was he in the past (he is needed to be figured out thematically).".
I'd assume that he's not being worked on for now since IronStylus also said that currently all the VUs they are working on are bundled with a gameplay update (They're basically doing it because they see gameplay updates as opportunities to work on champs, visually, that they may never have the time, resources and chances to work on ever again or at least any time soon).