I think mage supports need to be reworked. A lot.
It's a bit of a long read, but it's broken up into sections and paragraphs and crap so it's easier to look at:
: No one likes fighting her. She's not even ban worthy right now but people keep her on high ban priority because she's annoying. She just sits back, doesn't interact, and spams W. Even after all the changes Riot made, Soraka lanes are still the most non-interactive, boring farm lanes in the game. It's cool that Soraka being there twists the idea from "focus the adc" to "focus the support", but if the support is straight up in a bush 24/7 or almost fading into the fog of war almost all lane long, how do we do that? Too much of her value as a champ is front-loaded into W.
: Packs way too much of what a support needs to do for a team all by herself + she's almost as non-interactive as Soraka. Hard cc? Q. Heals? In her ult. Slows? That's W. Movement speed buff? Passive. Attack buff? E. Shield? E again. She's like the Lee Sin of supports...except she has the win rate the forums think Lee Sin has.
http://www.leagueofgraphs.com/champions/stats/janna/support/platinum
http://www.leagueofgraphs.com/champions/stats/leesin/jungle/platinum
http://www.leagueofgraphs.com/champions/stats/janna/support/diamond
http://www.leagueofgraphs.com/champions/stats/leesin/jungle/diamond
: So bad at supporting she isn't even known for supporting anymore, yet she's primarily designed as a support. Her situation in the game makes as little sense as her view of reality. Why is a support's lowest win rate in the game in her intended role for this long without anything being done about it?
: Isn't getting touched for the immobile mages patch, so if they did a group patch for supports, it'd be nice to do something about Karma there. Due to the way her kit is, she sucks at both being an apc or a support. Her only hard cc is a very delayed single-target snare, and due to how long it takes to pull off, her spell rotation, which is only 2 spells, isn't even viable to attempt after laning during team fights, so she becomes a Q-bot. Sure, her R + E is a thing, but most people would like a support's R to just stun/knock back/knock up a group of enemies...not make you run faster into hard cc. Her kit's design just falls off way too hard after laning phase.
: Skill floor's so low that the only way to keep her balanced is to make basically all her numbers for stats, scalings, and bases just as frustratingly low. Now most Sona players just opt for ap builds since the champ is entirely useless without it. She's robbed of the ability to flex pick because there's basically no way to make a solo-lane build viable without making her duo lane build straight toxic. She's seen as a jack of all trades, but not only is she a master of nothing...she's just not good at anything. She lacks very staple things supports pack in their basic spells, primarily hard cc. Things she does have are all granted at extremely low values due to the possibility of tagging 5 people. Due to this, she can't roam efficiently and she's nothing but a victim with no way out
in
certain
match-ups
. She's basically unable to function beyond an intermediate level in most instances, and trying to do so will put her in at extreme risk of dying to a sneeze.
: Extremely high skill floor, but the payout for it is surprisingly lack-luster in most instances. Given how hard it is to land her shit since everything she does is so ridiculously slow moving, you'd think she'd be more rewarding when landing more Q's and R's. Basically, even though she's relatively designed well, her skill floor's so high that anyone could just pick a champ that has an easier time
peeling
or
engaging
and get the same job done efficiently with way less hassle.
: Skill floor is surprisingly high for a guy with two lives...because it's so hard to hit anything with Q. At least since his Q has a huge .9 ratio for farming + his ult is literally life insurance, he sees a bit of pro play in the mid lane, given how pro play loves safety.
As it stands, mage supports are either:
-
Non interactive while getting tons of mileage off of spamming a button on their adc. 
-
Offer nothing of real value that someone else can't do better
, and are relatively worthless at higher levels of play. 
-
Are venturing to solo lanes. 
Only mage support that truly feels right that people appreciate is Bard, hence how much love the guy gets for being fun + he sees pro play while still being a rather difficult champ to master. All your other mage supports got serious design problems while tank supports are just better designed and better fit into the game. Definitely would like to see an overhaul in this area.

+ Windspeaker's would be great on Lulu if that's the case, even if it's only one target.