I think it's fine he can't do it.
But I also think we need more abilities that can take down turrets. Would really help some champions like Cass who just can't get a roll. Making her actually into a champion would take the ADC roll would mix a lot of things up. As it's the only team position defined by a roll(Marksman). All other lanes can see a mix of other rolls. Any time the ADC roll is played by another roll they get nerfed. (When people were using mages, they got their base AS hit. Making AS items less effective. Thresh got the same thing.)
All they'd have to do is make it so towers with her W under them make her auto attacks do bonus magic damage. This bonus will scale off AP and levels like Azir's W. So you can't just rank it first and gain overpowered tower killing power.
Many champions could fill this roll too. Veiger is one. Only problem would be his stun would be an amazing gank tool. This could be changed into a 50/60/70/80/90% slow + silence for the same duration. Or a polymoprh. It will still be a very effective CC. But this makes it much weaker without ranks. A 90% slow + silence is really close to a stun as it is. Then they could add "Units and structures within his E take bonus magic damage from basic attacks, this does not work on targets effected by it's slow.".