How to nerf Sona (QQ)

Writing this sort of makes me sad, because I love Sona, and it will make me sad for her to be weaker.  However, I do think she's OP right now, and nerfing her is 100% reasonable.  This is in response to this Riot forum post.

For anyone reading this post linked from there, I have 700+ games with Sona and I wrote this approved Sona guide on solomid.net, so I actually know what I'm talking about.

• Nerf her ultimate.  This is what I would like to see targeted most of all.  Ways to do this:
• Increase the cooldown (not recommended---I hate nerfing champions by just increasing cooldowns.  It just makes it feel worse to play the champion.)
• Make it do 0 damage (this is reasonable but sort of silly and doesn't really address the issues---her utility is crazy-good)
• Return it to the DOT that it used to do (fine, but not sufficient, see above)
• Decrease the stun duration:
• Everywhere.  That would be okay, but I would rather see
• The farther you are from her, the less you're stunned for, or
• The closer you are to her, the less you're stunned for.
This is my favorite option for nerfing Sona.  Make her stun variable duration depending on how far you are from her.  Either way promotes more creative play from Sona.  If close-range stuns last the longest, you want to make sure you're right on top of your ADC so you can stun the diver immediately.  If long-range stuns last the longest, you actually want to be staying decently far from your ADC so you'll get the longest stun possible.  Obviously this also opens additional counterplay options against Sona, which is always nice.
• Decrease the area.  This would be okay to be honest.  I would hate this change because it's ridiculous how much intuition you get about the area of a skill, but it makes sense: her AoE is really big, and if you want to keep the same duration stun why wouldn't you just nerf the area.  But I'd rather see the stun duration changed.
• Nerf her auras.  There are a LOT of ways to do this.
• Just nerf the numbers overall.  This already happened once.  I don't suggest doing it again.
• Make her auras decay over time.  THIS IS THE SINGLE BEST WAY TO NERF SONA.  We already have a decay of her W from double bonus to single bonus after 3 seconds.  What I'd rather see is a decay per second from double bonus to half-bonus over a slightly longer period, and I'd like to see this on all three of her skills.  So if she's completely oom and can't refresh her auras, she's basically screwed.
• This doesn't punish active Sona play that much in the short run
• If Sona can't be effective in the short run, it massively punishes her in the long run
• It massively punishes passive Sona
• Increases Sona's skill ceiling (not that she's not already really complicated, but this would make her more challenging in a good way and reward coordination between her and her ADC.  And no one can say that Sona is intended to be straightforward to play with her passive)
•  Make Sona's auras do less to herself than to her allies.  This is a BAD change to Sona, as it would encourage passive play.
• Make her residual aura after she switches stances last for less time.  Please no.  Being able to go E --> Q --> W without losing the defense aura for any time but giving yourself the Q-chord against an objective/in an allin is actually pretty important, in my opinion.  And more importantly, if you're running away with E persistent and you have enough mana, you want to Q --> W --> E and then get the E-chord off on whoever's chasing you without losing your MS for any time at all.  And to be honest, nerfing that is just going to make people who main Sona sad without actually adjusting her balance sufficiently.
• Nerf her Q/W numbers.
• Cut down on her early damage.  I would hate to see this because (1) it encourages passive play, and (2) it takes away a lot from what makes Sona herself
• Cut down on her W heal increase per level and increase its AP scaling.  I like this because it rewards healing from a Q aura as opposed to a W aura.  (I like this idea a LOT.)
• Increase her mana costs.  I actually don't think this is a good idea unless it's in conjunction with 1-2 other things also, because her mana costs are already so high that increasing them further to make her be balanced on that alone will make her lose at all but the very top levels of play in terms of coordination between ADC and support.
• Nerf her base stats.  Please no.  This is another really delicate line to cross.  I already feel that flat HP quints are 100% necessary on her; nerfing her base stats more will just lock item builds/runes without addressing the real problems.
• Remove the auto-attack reset upon getting a power chord.  I don't actually recommend this, but it would be better than some changes.

So, yeah.  I may update this post as I come up with more things.  The last thing I want to say is that I don't actually think nerfing Sona is as appropriate as buffing other supports, and I'd rather see very slight nerfs to Sona and more substantial buffs to other supports.