Kayle

Yes.

She COULD be used as a support but she is outclassed in almost every way as A:her W heal is on a long CD at 40% CDR and is nothing early game. a lv1 could do more then a lv1 or 2 B:her slow is point and click but it's not as good as other slows. can make the ADC slow can get an infinite 99% slow gets an 80% slow a level 1 and gets a 60% slow at level one while still doing high early damage and the slow can be a stun if you fire it right C:her E gives her AA splash and range. not VERY useful apart from some poke I guess...but a lot of supports have SOME form of AOE D:so that kinda only leaves her ult. 2-3 seconds of invincibility is a lot of time to do something. but your better off bullying the top laner then using it in a teamfight late game as your jungler picks something tanky

Yes you can play Kayle support, but you need to pick the right runes and know what you are doing... which goes for every other support

I would say a BIG fat NO. Here is why, her heal takes too much mana to use, she offers little to no dmg on Q and E and the slow on Q is just not enough to save your ADC from ganks unless you max it first which then leads to her Heal aka her W to suck even more. Her E is based off of her own AD and missing hp of target and early on with support items is effectively useless. If you guys manage to have a passive lane and you are able to get klepto procs that is if you run klepto still you may get enough gold to buy real carry items and not support ones. If bot doesn't get camped that is which is almost never especially if there will be a kayle there.