Once again, I feel a need to disagree on this premise completely. We have a component item with Grevious Wounds for tanks and AD because for the most part, they have longer, drawn out combat patterns. Someone at 100% HP fighting with sustain will have a longer time to be able to sustain against other ADs or Tanks, so from start to end, you need GV to help against those fights in the beginning to end. Sustain beats DPS, so early game where DPS is at the lowest, you need an early game counter to sustain.
This is not the same for AP champions, with Azir and Cassiopeia being the outliers. A majority of AP champions have burst and a combo that typically nullifies their opponents ability to react (Knockup, Root, stun). AP Champions shouldn't get a component AP item because they have a higher level of burst, and the ability to kill without giving the opponents a chance to sustain in the first place, where a DPS or Tank champion have to fight for much longer over time.
Giving AP a component item that has GV early, something to sit on while you build other things, shouldn't be a thing because not only does that mean you get higher burst, which means your enemy doesn't need to be that low on HP to be killable, but also allows you to gimp their sustain afterwards, letting you keep them in that still burstable window when your combo is back up. That sorta power shouldn't be given at a lower price, and should be kept behind a large gold purchase.
To refrain my reasons simply, AD and Tanks have GV early because they require to get a champion from 100% to 80% to 60% to 40% all the way till they're at 0%, where sustain could make that from a 20% window per to a 10%. Mages shouldn't get a GV item early because they're far more likely to go from 100% to 0% with an ult combo, or 100% to 40% with a regular combo. By giving mages GV early, not only do you let them have that 100% to 40%, you remove the ability to fight back at 40% as well, instead of possibly turn a fight back on the mage if they have sustain.
Sustain counters DPS and Burst counters sustain.
