Almost no reason to use Powerchord - Staccato?

The damage increase is almost negligible at 40%. Outside of laning phase where you simply use it for mana efficiency, Diminuendo and Tempo simply outclass it now. If an enemy gets off even one auto-attack during Diminuendo, it will have prevented more damage than Staccato would have dealt. Tempo is far better for securing kills, any additional aa will outdamage Staccato's bonus for the majority of the game. If you've taken any damage, it's always better to fire off Diminuendo during a trade.

While making it deal more burst damage wouldn't be healthy, it's just so lackluster that it's pretty much a trap choice at the moment. Maybe if it debuffed an enemy to take extra damage (whether % or a flat amount) it would actually fit its role without leading to Sona's absurd poke dominance.