The update sona needs
Sona is clearly a problem case for riot not knowing how to put her in a better place. I think a real part of the issue with her is the extreme mechanical simplicity of her kit means that she is in a make or break state based on the numbers on her abilities as we are seeing now. Her power chord interaction with her abilities is supposed to encourage thinking about which ability you choose use it with but late game the best general way to play sona is to use her abilities off of cool down. And with her low cooldowns it is how she often sees synergy with sheen, and simply looks to have maximum uptime of the power chord bonus damage hence the use of abilities off of cooldown.
I think a simple tldr of what sona's passive aims to achieve is taking smart advantage of her low cooldowns, while making deliberate choice of what ability you want amplified by power chord at the time so it isn't so mindlessly spam of QWE.
Sona needs an update badly to properly live up to that design.
POWER CHORD Every 20 seconds sona's next ability is empowered, gaining bonus strength and instead of costing mana returns 50% of it's cost. Power chord has it's cooldown reduced by 1/2/3 (at levels 1/5/10) every time sona cast an ability.
Hymn of Valor Sona and each tagged ally champions send out two bolts of sound that deal magic damage to the nearest enemies, prioritizing champions. Power chord - Staccato: Sona and each tagged ally next auto within 3 seconds deal bonus bolt damage also. All bolts deal 40% increased damage. MAGIC DAMAGE: 15 / 25/40 /60 /85 (+ 50% AP)
Aria of Perseverance Sona and tagged allied champions receive a shield lasting up to 1.5 seconds and healing for the remainder of the shield value after. Power chord - Diminuendo: Shield increases by 0.5% for every 1% of target's missing health. SHIELD STRENGTH: 30 / 60 / 90 / 120 / 150 (+ 30% AP)
Song of Celerity Sona and tagged ally champions gain bonus movement speed for decaying over 2.5 seconds. Power chord - Tempo: Movement speed no longer decay's and now last 5 seconds. BONUS MOVEMENT SPEED: 16 / 17 / 18 / 19 / 20% (+ 7% per 100 AP)
Crescendo Cooldown 100 seconds at all ranks Active: After a 0.2-second delay, Sona plays an irresistible chord in the target direction, dealing magic damage to all enemy units struck and stunning them for .5 seconds. Passive: Crescendo gains empowered effect depending on the previously cast ability. hymm of valor - gains 50% increased damage | aria of perseverance - reduces effected enemy target's damage output by 20% (+ 4% per 100 AP) for 3 seconds. | song of celerity - increases the stun to 2 seconds. MAGIC DAMAGE: 100 / 150 / 250 (+ 60% AP)
