[Patch 1.0.0.154: Preseason Balance Update 2] GD - Page 16

Simple thought experiment here
-Udyr is now invulnerable to all damage
Obviously the most powerful champion in the game bar none
Scaling down
Udyr now has -50% damage reduction from all sources at all times
same deal
and we keep scaling down and you see tankiness is directly associated with viability of udyr. You can outrun basically everything and small % uptime of CC spells are only significant if you are losing so much hp in that time that you cannot continue chasing. This leads us to the realization that ALL udyrs potential problems come from tankiness. Which is why people build mostly tank items.

However mobility items and damage items are important to a point
-mobility reduces time taken to reach target, reducing incoming damage and making ganking easier
-a small amount of damage items significantly improve your damage output and dueling potential due to your massive ad steriod on R (95ish), and doubling your damage output is the same as doubling your tankiness for dueling but it's much easier to go from 100 DPS to 200 DPS, say, than from 3k hp to 6k hp. Obviously we skew about 50% more to the tanky side because you have to survive potential burst damage that will target you if you are squishy enough to kill you, so if you're tanky enough to avoid focusing you down as a viable option (this is a combination of tank stats AND timing and playing with your team, if its 5v1 it's always best to focus the 1 dude no matter how tanky he is)

Other comments:
"it helps tiger udyr more"
this is definitely wrong. A 12% steriod on your resists means the more hp and resists you have, the better it gets. Pheonix basically relies on a critical mass of tankiness to dive the targets you want to dive. You basically have to drive through a brick wall and if that 12% resists is like 25ish armour and mr it might leave you at 70% hp instead of 50 or 60% (depending on poke and shield usage, for example) which might be enough to continue diving but at 50% you can't 1v1 anyone and people can start using ignite on you and stuff.
Tiger udyr has more scaling later on damage (especially hitting 2 Q's in a row when first going in on a squishy) and bursts harder meaning you tend to build more damage and simply bear stun+q is noticable, while pheonix udyr you want at least 3 hits of r and preferably 5 seconds+ of aoe pheonix damage meaning you're in for the long hall.

"shyvana is less tanky than udyr"
this is downright ignorant. Udyr has a 6 second shield for 200 damage shielded. The later the game goes, the less significant this is, since heavy resist stacking is extremely hard, hp scales up tons just from leveling and is everywhere on items. Shyvanas flat magic resist boost of 40 mr/armour at for example 4k hp when you dragon form in is really strong. Also a shield scales the longer the fight lasts. Trying to focus down a shyvana who jumps in is MUCH harder than focusing down an udyr. Combine that with the fact that If you focus shyvana you focused someone who used her main burst with W R E Q, while you can kill an udyr before he does anything at all.

As scip rightly pointed out, udyr needs to punch people. ALL udyr can do is punch people. The only damage he has not based on auto attacks is the 67 DPS from the pheonix stance activation. EVERYTHING else he does is based on melee autoing people, and any passive threat he has to zone people is purely based on threat of running in and punching you, so the more people you can ignore to go in and do that the more of a threat you are.