Who thought Sona needed a nerf? Anyone who has played against her.
-Oppressive poke
-Outrageous sustain
-Locket shield every few seconds
-mini-Talisman speedup every few seconds
-Can't catch her. Can't catch her team. Can't run from her team.
-Ult that can be used for engage, disengage, and can completely change the outcome of a teamfight.
Sona in ARAM is auto-win.
Fizz? Single-target. Once his CDs are blown he's harmless.
Kat? If you didn't bring the one stun it takes to shut her down, that's your problem
Morg? Point taken. She's auto-win in ARAM too, but she takes a little more skill.
Vayne? Really capped by the skill she takes. A good Vayne is ridiculous, but good Vaynes are few and far between.
WW? Useless without items.
Lee Sin? Again, takes skill. An average Lee is nothing but a feeder.
Sona is easy to position, and positioning is all she needs to do her job. She's the reverse of Mundo -- instead of a tank sitting in the enemy team burning them down and slowing, she's a squishy who sits in her team healing and speeding them up.