Idea for a Sona "rework"

Basically i hate that sona doesn't do anything in lane and late game is a spam happy monster.

So i decided what if Riot made her buffs A LOT stronger but requiring more effort to min-max? What if Sona's buffs "stacked" based on the duration of time an ally is inside the area? I'm thinking something like every half second the aura "pulses", applying one stack of the corresponding buff. The aura's remain up for 3 or 4 seconds. Upon leaving the aura area and/or receiving a full buff, the ally gets a "debuff" that prevents them from being effected by the same aura again for X seconds, maybe it falls off if they are effected by a different aura. The basic idea is that it forces Sona to stick close to her allies rather then just zip around tagging them with the edge of the aura. Also since the buffs require prolonged exposure to be "good" it means that Sona has to choose between spamming low-ish power abilities OR helping her team with strong buffs.

Hymn of Valor: not sure if i want to keep the auto target bolts or change this to a skill shot with a much higher damage output, since it would remain Sona's only basic offensive ability. ANYWAY the aura gives a +5 AD/AP per tick, with a growth rate of 2.5 per rank into Q, buff to allies within the aura (buff lasts 1 second after aura disappears)

Aria of Perseverance: I'm stuck between a flat % decrease in damage taken while inside the aura OR a shield that triggers upon leaving the aura / taking damage. Shield remains for 2-3 second after aura disappears. Again the idea is that Sona has to stick close to her ally to give meaningful bonuses. The idea to have the shield stop stacking upon taking damage is a means to counter play against the ability, since players can tag the effected champions early and prevent them form coming out with a HUGE shield. I'm thinking the shield gets to her current after half the duration, if the aura lasts 4 seconds allies would have to be inside for 2.5 seconds to get a shield that's stronger then what Sona can currently do. Each pulse has a flat amount of shield given and an AP ratio of like 8-10%.

Song of Celerity: Champions get a stacking movement speed AND attack speed buff while inside the aura. Maybe this one doesn't stack but keeps refreshing duration while allies are inside, then has a moderate up time once they leave the aura area.