Sivirs shield should at least return enough mana for a free Q.

Sivir's shield and Ricochet are really the only things that separate Sivir from the other adcs. I am not sure what is going on with Ricochet, but I think Riot should focus on making Sivir's shield one of her defining abilities.

Several adcs like Jinx, Corki, Ezreal and Lucian are very dependent on using abilities to deal damage unlike other carries who deal damage mainly through auto attacks.

I feel Sivir would be a much more rewarding adc if her shield refunded enough mana to let her use her Q. It sets up good counter play. If the enemy carry or support messes up and gets their ability blocked by her shield they now get punished with a boomerang. if Sivir messes up and wastes her shield she is down mana, and is even more vulnerable to enemy harass especially as Sivir can't trade effectively without her boomerang and shield.