Almost anything can support
Support income right now is not as good as a typical farmed character, but it's more than adequate to get a functional set of items. It's increasing viability of champions across the League as more and more characters with bad laning phases get in on the action. Support items guarantee gold as well as health/mana sustain, and characters that would normally get bullied out of a good laning phase and weren't viable in the jungle suddenly become threats.
There are a few exceptions to the rule ,of course; characters that push excessively and/or don't have any playmaking power still aren't very ideal in the role. Most of these characters (such as Vlad and Shyvana) fit just fine in another role. The only character I'm at all worried about viability is Heimerdinger, but his recent rework did a lot to help him out in mid and possibly top lane. Virtually every other character does well as a support now or already performs fine in another spot.
Dawn of Annie (and other mages)
Tabe's support Annie took the world by storm prior to the World Championships. Zyra was a preferred meta pick in Season 3. With guaranteed gold income, these support choices and other similar ones (such as Lux and Orianna) have become the new choices to beat. I would not be surprised to see support Kassadin become more preferred than mid Kassadin.
Annie is probably the biggest offender. Before 3.14, Annie did gobs of damage and had a long-duration stun, which she could hold indefinitely as a threat. Even if her stun didn't get a kill, it almost guaranteed damage. Furthermore, simply having the stun available crippled any offensive plays by the enemy that didn't involve CCing and killing Annie first. And finally, the massive range on her basic attack allowed her to get in free damage constantly where other characters would not.
In the late game, Annie played the role of a typical Sona, only with greater range and game impact. Her ultimate delivered a large AoE stun and a powerful pet that racked up lots of damage. In the chaos of a teamfight, she was a beast.
And... now Riot's given Annie money. Annie without money dealt reasonable damage, especially with her ultimate, and was incredibly dangerous throughout the laning phase. Now, getting behind against an Annie lane usually means being forced to hug your turret because her burst is as threatening as midlane Annie and marksmen typically don't build magic resistance until very late.
Zyra is similarly powerful, as are Lux and a slew of other supports that can make plays, deal good damage, and scale well with items.
Bye, normal supports -- we'll miss you
On the other hand, the true supports got dunked by Riot. Said the devs in the 3.14 patch notes, "We had to tweak numbers to ensure certain champions didn't become oppressively powerful." In layman's terms, this means that normal characters with CC effects (like Fiddle and Annie) were unchanged, while the characters designed for the role had their numbers slashed as if they were on sale for Black Friday. The fact that they were also on sale on Black Friday seems a bit ironic.
Sona had the AP ratio on her Q (Hymn of Valor) cut but was given an AP ratio on Power Chord to compensate. Her auto + Q + Power Chord combo still has a 3.0 AD + 0.7 AP ratio plus the base damage of the two spells. In case it wasn't clear how Sona should build now, Crescendo also had its AP ratio cut. Overall, Sona is one of the more viable conventional supports now, but she should probably be building tanky or AD rather than AP.
Janna is pretty much unplayable right now. She gained an AP ratio on the slow of Zephyr, but at .06 she needs several hundred AP before the increase is notable. The AP ratio of her shield was also reduced, and the damage on her tornadoes was completely gutted. She gained an AP scaling for the AD buff on her shield, but it is small and doesn't really make up for the loss of damage on her tornadoes.
Lulu mostly plays the same, though the damage on her passive was slightly nerfed. The damage on Glitterlance was unchanged, and the AP ratio on Help, Pix! was nerfed a bit. She is probably most able to play the way that old supports were able to and still provides more utility than a typical mage. Also, she can build in a variety of ways, which helps her stay viable. Nami is similar, though she had more tweaks than Lulu. Nami is less able to build hard AP than Lulu is, though neither champion really wants to.
Taric and Leona were buffed. If you played them before, then you know that holy cow they are good now. Taric is a lane-wrecking death machine; Leona is an unstoppable engine of mass destruction. Armor and health ratios rather than AP; both deal tons of damage and are more durable than ever. Add money into the mix and these two are nigh-unstoppable if they get rolling.
Probably the weirdest of it all is that people caught on so quickly. Out of the last dozen or so games I've played, support has been far more contested than ADC/marksman and nearly as contested as mid. It's easy to play, you get to play super aggressive, and you have less responsibility. What's not to love?
Of course, I'm still horrified at the thought of support Kassadin. Riot, please nerf.
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