Udyr PBE blow to passive will be his undoing
udyr passive nerf looks excessive, particularly the movement speed nerfs.
Having to have the element of surprise is essential when ganking on udyr. Udyr ganks can be seen coming. learn to keep and eye on mini map and ward (let's not downplay this essential part of the game). Instead why not make a warding tutorial for new players. Have them extend beyond halfway across the lane and instruct them on how to avoid an incoming gank. And really stress its importance, make it difficult to complete this stage. Could also do one for vision control/denial.
Udyr ganks aren't nearly as scary as leesin, xin, vi, jarvan, zac, amumu, ekko, Elise, gragas, skarner, fizz, pantheon, nunu, nocturne, rammus, hecarim, shaco... Any ranged jungler with red buff like nidalee, or kindred, tf, graves, lissandra hell even kassasin has better ganks/tower dive potential. Many junglers have more bursts.
I don't mind nerfing udyr, i want every champion to be balanced, but don't kill his identity. He's good at split pushing and can at the very least pull off a successful gank if played right. His team fighting is mediocre at best. Its hard enough to stack 3 stacks of passive and have enough mana left over to both pull off a successful gank and or escape if things go sour. Sorry midlaners no bluebuffs for you. Maybe runic echoes gives enough mana but the other jungle items don't.
Udyr is ripe for a 'furlift', consider this:
Every so often gain a charge that allows you to enter a spell on CD just for its passive (not active). Highlight spells that are on cooldown if you have a charge available, to signify that you can reenter the stance for its passive.
Example I enter bear form to stun the adc, enter phoenix or bear form to damage them, now immediately enter bear form just for the passive not the active ms buff and flash onto support.
The issue is how effective CDR is on Udyr right now. Not using him for what his passive offers as much as actives. I'd like to see cdrless udyr be viable. Udyr that derives his strength from effectively using his passive and choosing wisely whether he'd prefer to lifesteal, stun, or do dmg. As opposed to spamming bear and turtle stance to shield himself and run fast or proc sheen. I'm not downplaying CDR udyr either it's fun, there's just this untapped side of him could also shine. An Udyr that would favor the oft overlooked frozen mallet over IBG.
This is the markings of a well designed champion. One that can be played in drastically different yet equally viable ways.
Keep in mind using a charge to enter a stance will not refresh his passive.
His kit is limited by his inability to access his other passives. CDR is the best/only way right now to switch between passives asap. I don't think it should be the only way.
with no stats that carry over into champion fights. That's the main reason Udyr shines in this meta.