It's the fact that 
is overtuned.
Nerf the movement speed from 10% to 5%
The other MAJOR problem is 
The price needs to be increased from 500g to 800g.
But given Riot's track record they will just nerf Udyr before they even nerf Swifties and Runic, after which he will be in a much worse state than he was way before the items.
Devourer Udyr has a 56% winrate. Udyr is OP, it's not just the items.
He is a ball of stats that deserves a rework anyways.
that's 300 gold increase on tier2 boots mate. are you sure, you are being reasonable here?
What are you going to do about AP junglers after nerfing the movement speed by 5%? (holy shit, that's a lot).
isn't problem
is
THAAAAAAAAAAAAAAAAAAAAAAAAAAAAAANK YOUUUUUUUUUUUUUUUUUU!
I thought I was one of the only people who felt this way!
Something is wrong with a champ when he can basically engage when he wants, pull out when he wants, unkiteable, spam ghost the entire map with no mana issues, twist is abilities non-stop with no mana issues.
He can build any combination of tank/jugg/fighter/ap burst and he honestly sacrifices nothing to any of the builds. He's been a wrecking machine this entire time, for some reason he's just recently gotten to the point of "nearly impossible to deal with."
He's probably the only champ who has no weak points. Even if he gets caught out of position, unless you have some hard CC, he can pull out and you can't catch him.
It's nothing to do with certain items, he's always been crazy good, he's a jack-of-all-trades and has always been. It's just a few champions out perform him in certain metas even though he's just as good, he's just been over looked because of "X champ" does it a little better.
I agree.Please you don't touch his base stats.
Udyr making far too good use of them doesn't mean other melees should have to suffer. Nerfing swifties until Udyr doesn't use them well would make them useless for the rest of the cast. Yes, they need a cost increase, but lowering the stats to ineffectiveness does nobody any favors. If Udyr is too fast after RE gets nerfed, they'll probably have to look into lowering his base MS.
RE being powerful on him isn't just RE. Udyr has been over-tuned for a long time. He's a champion that can just brute force things through sheer numbers, since all he does is auto attack with modifiers.
I don't see other champions with up to 100% bonus attack speed permanently and a slew of other on-hit bonuses while permanently having ghost active and a spammable shield as a tank and 6 second CD stun.
Maybe if they took away the phoenix priming on activation, but as it stands his numbers are overloaded for the game's itemization now. Slamurai Jack is not wrong.
Just because no one is running hard CC tank comps nowadays doesn't mean Udyr is OP. You can't run 3 ad squishy champs and expect to not get run down by udyr. comon.
Runeglaive: 1625g +250 mana +40AP +10%CDR
Spellblade: 100% base AD +30%AP, doubled against large mobs Runic echoes: 1625g +60AP +10% movement speed
Echo: 80+10%AP, times 2.5 against large mobs
Runeglaive was changed because only a handful of mages could actually use it. Mages, the champs the item WAS DESIGNED FOR, have low MS to begin with usually. in the 325 to 335 range. nerfing that would be a HUGE nerf to ALL potential mage junglers. AP udyr has always been very powerful; runic echoes just gives him a logical slot item for the jungle. otherwise he would just get runeglaive and replace it with ludens anyway.
