Why dont people play Urgot more?

I just bought Urgot in preparation for the pre-season 6 marksman changes. Since I heard he was a good anti-carry, I decided that I should learn him just in case things gets too out of hand.

What I found out, was that he is astonishingly easy to play with really good results. I played him in mid and as adc. In mid, I decided to to start with the mana crystal and 2 hp potions. I was able to out last the other opponent and they couldnt even burst or outpoke me because of my tankiness and shield. Once you land your E though, it's all over for them. It's kinda like Cassiopeia with a more engaging playstyle. E,Q,basic,Q,basic,Q. Boom, theyre at 1/4th hp. Late game, you just sit in the back spamming Q and waiting for the right moment to ult the right person.

Speaking of that, when I was in bot, I was against a vayne. I was able to outfarm and outpoke her in lane and she had to go back twice. When she hit 6, she tried to all-in me, but with a well timed ult and shield, all her dmg was negated and I proceeded to just Q,basic,Q,basic,E,basic,Q,Q and she was dead.

I don't know why I don't see Urgot more often. He's actually really good.