Didn't really realize how viable it is. At least in normals.
He doesn't heal, and is squishy, and that's about all of his "cons". I think he is more useful in helping an adc snowball early by securing kills in early game.
A stun followed by his Q and AA to get his magic damage bonus set up the adc for an easy kill. By the time late game and end game rolls around he can actually help bursting other enemies down more so than Nunu or other lower tier supports.
His ult is helpful for ganks and for locating enemy champs, and everyone gets 2 gold per minion kill.
I'm not saying he is better at support than Taric or Sona, but in that hybrid role of a non traditional support (Nunu) he excels.