[{quoted}](name=WE Mizaya,realm=NA,application-id=3ErqAdtq,discussion-id=zgAzn6mq,comment-id=000300000000,timestamp=2017-03-07T00:43:32.779+0000)
Anivia has a 4% pickrate support at Plat+ Syndra 1.6% , Ori 0.6%. They aren't really considered as supports. You can play a lot of mids top too, doesn't mean that they are worth considering as having something to do with the meta of that lane. If you want to find out what makes supports good, you look at the highest pickrate supports, or, in this case, the highest pickrate AP supports.
The reason Anivia isn't really a good support is one reason and one reason only, at least in my opinion. Her mana costs are out the roof so you can't really use your abilities consistently as a support where you don't have that much mana regen unless you're building all those support items that Anivia doesn't really synergize with. Orianna I could most definitely see being played support, except for the fact that her high damage in the mid lane combined with her shields and initiative ability basically makes her able to be a second support already. Syndra uses minions as bombs...This causes the ADC to lose out on farm if she does it enough, aside from that all of her balls would have to be cast inside the wave, and she has to use them a decent enough bit, doesn't have to worry about it killing minions in the mid lane however. I dunno if that really matters too much though considering Zyra, but that's the logic I'd use, aside from that she only has one useful ability for a support aside from her delete button, and I don't play Syndra so I dunno if it'd be called a delete button with a support's income.