Are characters like Annie and Zyra really 'supports'?
The meta of League of Legends seems to be shifting, instead of using for example: Nami, Lulu and Soraka as supports, people is using Annie, Zyra and others to fill the role.
When one uses such characters in the bot lane, are they really in the support role? Most of these supports have full AP builds. For me, they're not really supports, for me it seems that they're just using mages in the bot lane.
I guess that people is calling such characters as supports just because tradition, and then independent of what you put in the bot lane, it's going to be called a support. I believe that in RPG games, a support is a character that is completely diffent of, say, Annie and Zyra. And also that the idea of supporting comes from there.
What I don't agree is that they're being called supports. It's like if the word support is being used as a synonym to companion. I believe support is a class of characters that have a pattern of skills for helping in a specific way, and not helping in all ways.
Solution 1:
The question is hard to answer, mostly because the notion of supporting is vague. There is no clear definition of it when it comes to the game itself. Also, you cannot apply the terminology of another type of game. Since their is now particular definition for the game, I can only respond to the question based on the dictionary.
Dictionary will say that supporting is "to act in a secondary or subordinate role to (a leading performer)". With this definition, Annie, or Zyra can be used to support an AD Carry. Their main function is not to provide a burst of damage, like they would do as midlaners, but to be able to reliably control the enemies by landing stuns or root.
Of course they will build more like mages in the end game, mostly because their kit benefits from AP more than other stats. But traditional supports tends to do as well now: Lulu shield, speed boost or slow also scales on AP.
Furthermore, itemisation of such supports will strongly vary from a mage build. They will more probably go for utility first, with Sightstone for Warding and Cooldown Reduction to ensure they can get more stuns and root.
As a conclusion, I think that supporting is not depending on champion (even if most champion would be weak supports). Support in League of Legend is a role, it is not a category of champion. For being a support, you need to be able to provide for your carry. That can be : crowd control, sustain, protection or maybe other things. In my opinion, the meta has not changed yet. Gamestyle, however, has.
Solution 2:
Like you said the meta is shifting.
"Supports" are actually becoming "secondary mage" nowadays, simply because they have loads of gold to spend. It is just not worth it for a "support" to buy support items (exception beeing the starting gold item).
In the end all that's important is to win the game. We know that AP botlane supports work really well, and so they fit their role completely.
Solution 3:
I think it depends on how you play them.
The main role of the support in the bot lane is to protect your ADC and give them gold (from kills and minions), so that they can take towers and deal tons of damage to enemy champions.
Annie makes for a good support because she has a stun, and her auto attack range is long (625) so with that and her Q she can poke away the enemy ADC and hopefully prevent them from farming.
Zyra makes for a good support because she has a snare as well as good poke with her plants. Also her one plant can slow, so a W then E combo to snare the ADC then slow them afterwards is quite effective in locking them down so your ADC can come in for the kill.
So they both have kit to be 'aggressive' supports, compared to lets say the traditional 'passive' support you are talking about, the ones with heals or shields or things of that manner.
If the support player plays their role, they know not to take minions, and to allow the ADCs to get the kills while they rack up the assists. As long as the Annie or Zyra do this, they are still being a 'good' support.
Likewise, you could have a Soraka taking all the minions with Starcall and stealing kills with the damage from Infuse, and she would be a 'bad' support.
So, in short, champions such as Annie and Zyra can be effective supports, they are just more aggressive than other support champions.
It all depends on the player who is playing the role.