Its because he's support (and not faceroll and op- ala sona). I haven't gotten to play much this week but he's a very strong character. Pillar is amazingly powerful as offensive support, his ult can catch a tank offguard changing the landscape of a fight and is on a considerably short cd. It can also make for pretty absurd diving. His other abilities are good, but E and R are what make him a strong pick. in the game I just played I was ganking so easily, I couldn't believe some of the kills I was getting relatively easily.
Also,I stupidly got caught in my forest while 4 members of their team sprung me at red, and included at least a sona ult and kennen, maybe a sion stun to, and I lived. Not many champs can pull that off, especially with no hp items.
Speaking of item builds, lol at saying LoL has boring builds. LoL has the most versatility that I've seen in mobas, the items available fill many many niches, you can build a champion almost anyway you can think up.
He's not talked about because he's not terribly OP. I think he's a strong and unique champion. But I'm a sucker for offensive support.