Just a little point to Riot, on why SOME will never play support. I will cover this with three main points. Because I LOVE support, I play it in many games and enjoy the concept. I play priests and medics and utility mages and engineers and on and on. However, I just... cannot play it anymore here.
1: The support is helpless.
If you are caught alone, you are dead. If you are a tank support you can only hope your HP lasts until you run to safety, if you are a healer support you are straight up dead. But more so, you are helpless to save the game. If I play a mage like Brand, I can singlehandedly win fights, not on rare occasions with superb outplays, regularly and easily. If I play Riven top I can easily make the enemy team rage quit. And if I play a jungle tank I can still do tons of damage while building pure tank. As a support, if my mid and top feed. I can do zip. I have zero carry potential. Now don't get me wrong, I understand supports are there to support their team, not to carry. But the problem with this is, is that it results in an atmosphere where you are putting in all your efforts into making somebody else look good and praying they carry you. If my support and ADC feed however, and I am Riven top, I can still go TP gank bot lane and get a double. Tilting the advantage and causing the enemies to lose confidence. Help myself snowball and carry harder. I have the power to mold my own destiny.
2: The supports are becoming more and more symbiotic.
I hate this. It was bad enough with things like Leona's passive or Taric's old heal. But more and more Supports are being molded so they have no scalings, their tools are all shaped to help the ADC and they are helpless alone. There is a problem, besides limiting build diversity and invention of new metas(Morg was not originally meant to support for example). You are taking away the potential for supports to have awesome tools of their own, that just happen to be more utility and support oriented, and instead making it so they are literally just an attachment of the ADC. This is... insane, at some point you will cross a line, where basically supports might as well just have no character on the field and just push buttons to buff, heal and defend the ADC. Like I get it, that is the support's primary role early game. But it worked just fine without all their abilities being molded around doing only that. We want our own, fun and cool utilities. That just happen to be good for supporting and utility. Originally, a support existed not because their ability said "Only works within 100 units of the ADC" it was because they had low gold requirements, good utilities and perhaps a sustain skill. We don't need to be hand crafted velvet pillows to carry the ADC on.
3: There is no reward for picking the least desired role.
"Support: 50% faster queue". Yet what do we get? Nothing, we don't get any independance, no rewards, nothing special. We just get dumped further and further into being a ward jockey ADC slave than ever before. If I pick the least desired role in WoW I get bonus gold, I can actually carry my raid through superb healing and tanking, and I am not helpless alone. Plus my character is not a symbiotic attachment to the tank, all my utilities, heals, skills and damage work just fine when alone. I just specialize in healing raids. In LoL? I get told "I was awful for going 0/3" of course leaving out the 35 assists. And the fact that without me the fed Vayne wouldn't have gotten fed to carry us to victory.
As for me, I am permanently giving up support. I use to play it primarily, gave it up once. Tried to get back into it recently. Nope. Another lost support. But for those still strong enough to tough it out, here are some ideas for Riot.
Give special rewards for getting assists, if you choose the support role, possibly even make assists appear first. And give supports more special interactions and mechanics based on assists. The same way carries get for kills.
Give supports more independance. We don't need tailor made abilities that might as well read "Take me instead" or "Praise the mighty ADC". That doesn't make a support. Morgana is considered a great support, and ALL of her abilities were made to work fine for herself, as she was originally meant to be a mid mage. I do enjoy some support focused mechanics like Thresh's lantern, but heck, at least he can use it as a shield for himself if alone. Just give us FUN and strong utilities, that are generally good for support. And make it so we are less gold heavy, so support is still optimal for us.
Give supports more ability to carry their team through excellent supporting. And I don't mean getting your ADC a couple kills so they get fed. I mean so that even if our team is behind and underfed, Soraka or Janna don't become next to useless other than a free kill with some peel. There are a few supports that can carry through supporting, but they are usually ones who weren't designed as supports, like Blitz who was originally a bruiser who ended up working well as a support.
Make more flashy and cool supports. Who do visually awesome things and have large, impactful spells. There are a couple, but it should be the normal, not the exception. It is perfectly possible to look awesome even if you aren't dealing damage or raking in kills.
EDIT: Since I doubt anybody here cares about MMOs, let me use another Moba as an example.
When I play Tyrande or Uther or Auriel. I do not feel like I am a helpless attachment to one specific carry with no power of my own. But regardless I am STILL fully a support character. I'm just not a LoL support... Mind you, I still vastly prefer LoL over Heroes.