I pretty much only pick Udyr when my team has some other form of hard engage. Got to pair him up with stuff like Zac top, or Oriana + any champ that can dive hard, Ashe, etc.Man... if everyone didn't have blinks and kiting ability that Udyr skin buy would be a no brainer.
As long as Udyr doesn't have to start fights I think he's an absolute monster. Bear Stance gives him more than enough movespeed to follow up on an initiation, and chain his stun, at which point his ******** amounts of damage murders everything.
Counterjungle, and countergank. That's basically what he excels at early on, so that's what I rely on. I don't really think any jungler can straight up 1v1 Udyr, the best you can really do is run away or hope Udyr overstays his welcome and your laner saves you. And his ganks are pretty meh until you start getting ranks in Bear Stance (screw Turtle Stance... Bear Stance gets more out of each rank than Turtle), so rely on counterganks.
Like, yeah Udyr has defined weaknesses, but you can definitely work around them and make him worthwhile.