Why is Sona been left useless for so long?

She's been beaten over the head so many times even when the likes of offered far more tankiness, far more CC, better shields. The only thing she even has going for her at the moment is a decent ult to initiate with which can be flashed by anybody since it has a delay and has a ridiculously long CD to boot.

And quite frankly I don't care about your winrate arguments. The circlejerkers were bitching about Zed when his winrate was 47% at one stage and also Fizz when he was just above 40%. You don't get to use winrates when it suits you.

Sona is weak. Her base stats are low even among supports, extremely low HP/Armor/MS. Her mana costs are high. Her CD's are high. Her poke has been gutted. Her healing/shielding sucks compared to any other support.

Nami heals more then double her early levels for less mana, only at rank 4 does her heal cost more and even there it's got better base healing + AP ratio and Nami/Sona should have or even at that point.

Riot says the Q is too strong, so then make the passive effect for W/E more noticeable and more people will use them. Bump up her base stats a bit and she should be viable again.