Ahri as a support?
Is this a good or bad thing? can she be played as a support champion?
Is this a good or bad thing? can she be played as a support champion?
Just because you can do a thing, does not mean you should. Anything will work if you're low enough elo and practice it often enough, but she's going to be utterly useless after the first 10 minutes if you don't absolutely shitstomp the lane with your adc. You need the extra gold for real AP so you can transition into an off-carry. Kind of like old Nidalee as support, except without the heal and defense shred on key targets.
I've been playing it on a low gold account 28 games in preseason 57% WR which is not great for what I should be getting.
http://oce.op.gg/summoner/userName=Aram+Prince
Although it can work especially in this damage meta...
I'd never play it in Diamond on my main, too many people think you are trolling and you lose because they are tilted and give up. That alone reduces your win rate by alot.
That and her support capabilities include 1 charm for 2s (if you max first) and... that's about it...
She has damage if you can get your stacks on mejias, but honestly so many other supports do so much more for the team and have much more utility/poke in their kits.
A good support either has pick (morg lux), engage (leona, ali) good base poke (brand karma) buffs (enchanters raka lulu nami) or protects (braum). What you'll find is most traditional supports do some/most/all of these AT THE SAME TIME and have heaps in their kit. Ahri just has pick with her E. Usually supports have great base kits filled with utility at the cost of low scaling hence don't need items to be effective.
Ahri doesn't even do as much damage as typical damage supports like brand (has better base scaling % health dmg and more cc upon rylias) or zyra (has more CC)
I'll admit she's fun and there isnt that many mobile mages so its great to have a dash around with her.
Honestly though, look into the kit of traditional supports and compare to Ahri and you can't deny her kit is based around herself not others.
Nami - Ally MS buff, AOE stun, ally/self heal / poke, ally aa slow, Ally MS buff AOE knock up disengage.
Ahri - Self MS buff, Mid range poke / self sustain, Damage, Charm, Self Dash / Damage
If you want to climb I would not recommend. Not saying you can't, you can, just not as fast/efficient as other champions. In normals though or smurfing for a bit of fun, she's fair game XD
Just no. Better play Brand/Zyra/Lux/Velkoz if you feel like playing mage bot.
She could work, has a good setup to pick off people with ult > charm, and can poke in lane
issues are that she will push the lane by harassing, and she needs levels to scale damage, so there are likely better options, but I wouldn't discard it immediately because no one does it, and it would be worth experimenting with
As a fun pick yes As a serious pick no Her kit doesn't let her scale as other champions so you usually need to be ahead to be able to do something, that's why she is a mid laner , 1 or 2 levels ahead of bot laners which are usually her main targets
ExcaliberPrime does it in D2-M so yes you can play Ahri support <3 uwu 
is counter so easily in mid lane so in terms of practice toss her to support as well.
Don't do it
I've used her, and she can harass very well, especially against some melee supports because they cant' afford to close the gap on her. She works very well as a poke support, and if you can land your charm, enemies are almost always going to die if your ADC is there to capitalize on it. That said, you DO need a competent ADC, as well as you've got to keep the pressure on with her, because she doesn't do well if the enemies are allowed to pressure her. Another think you need to concern yourself with is her mana, which is very intensive until you get a Luden's started.