Originally Posted by Healsforhugs
Yes, that makes them very good with AP, which is why they go mid more then they support.
Support morgana can't just go into 5 enemies and ult and get 5 stuns off on her ultimate, she'd explode. AP morgana with ROA/hourglass can. Support morgana and AP morgana are played drastically different. I'm not sure what your definition of "game winning" is, but there are better ultimates out there.
Typical mages (and the most popular supports) who go support have long range (not melee) AOE CC ultimates.
And that's what makes those champions so much better than other supports.
They're fully capable of branching out into other roles and not be a complete waste of gold.
Sending Lulu to mid is nothing but pure idiocy now that her ratios are garbage, she might as well stick in bot lane where her abilities are practically the same whether she's farmed or not. Imagine if instead of the Carry, you as Lulu or Sona just so happen to have scored all of the kills. You can't even make terribly good use of the gold compared to all other members of your team.
Lulu is an example of terrible champion design. She's about as useful fed as she is unfed. Pigeonholed so fiercely into 0 cs support.
Kayle, Morgana, Lux, and Zilean are well designed champions. If you want to babysit the carry all day, you're free to play 0 cs. If you want to farm up and have some fun, you're also free to solo lane or jungle. They're capable of being 0 cs, BUT if they happen to "steal" enough cs or get fed off champion kills, they can actually make use of the gold. Nobody cares if you feed a Sona, she'll be marginally better than an unfed one.