Whether or not you like the champion and the skin should be all that matters.
The removal of Feral Flare will hurt Udyr, but he was strong before it was introduced as well. Additionally, have you looked at the changes to smite and the machete enchantments yet?
Benefits for Udyr in Preseason 5:
-Stalker's Blade (smite does true damage and slows)
-Skirmisher's Sabre (smite makes next 3 attacks do true damage to target, gives shield based on max health, and vision on target)
-Enchantment: Slayer (attack speed, CDR, stacking attack speed)
-Enchantment: Juggernaut (health, movement speed, CDR)
I was never a fan of Feral Flare jungling because I like to gank lanes and get my allies ahead (or even, I guess), so I'm probably going to start spamming Udyr in Preseason 5 to figure out what combinations on the new jungle items and masteries work for him.