Personally, no. Urgot's goal is to basically be a ranged version of what Riot imagines Juggernauts to be... immobile, hard hitting, and able to take as much as he can deal.
Righteous Glory gives only minimal damage (from mana), no cooldown reduction, and the activated ability isn't really worth it as you shouldn't generally be the first person into a fight by using your ult to swap after popping it. You'll be fairly likely to survive any incidental damage, but with up to 4 other champions attempting to target you after you stole their ally from right next to them... leave the Righteous Glory to Singed or someone.
Better off getting defensive stats, cooldown reduction, and armor penetration. Not something that puts you at the front line every time you use it.
On another note, anyone else excited about
the new champion? Basically amounting to an ADC Jungle with a huge amount of utility (or troll potential) on her ultimate... though I don't feel her ultimate really meshes with the rest of her kit, and it seems sort of tacked on. An AoE, all target encompassing Dazzle-esque death stopping ability, that could potentially work for either enemies or allies doesn't seem to fit on someone whose kit it otherwise centered on hunting down enemy champions after passes through the jungle.
The passive also has huge potential to be broken, acting as follows (according to the League wiki):
Scoring a takedown on a marked target permanently empowers Lamb's basic attacks to deal 1.25% of her target's current health bonus physical damage, stacking with each mark consumed.
So you've basically got a free Blade of the Ruined King. And it doesn't mention stack limits, but you can't gain additional stacks from the enemy jungle after 6, capping at a hefty 7.5% bonus current health damage off jungle alone. Combine that with Devourer, and the fact that her 3 hit passive ALSO does a % of max health... seems like someone who needs to be shut down early and often.