Honestly, there's no good reason to not have an alternate QSS upgrade. It doesn't even have to be an AP item, it could be strictly a defensive item.
People always try to pull the "Zhonyas is like an AP QSS!" thing, but that comparison simply doesn't work. The reason you buy QSS is for suppression, and every suppression in the game is a targeted, instant-cast spell, so you can't react to them with Zhonyas.
There's no reason you should have to pay a 1500g tax to be able to lane against Malz from behind. There's no reason why mages at full build are effectively not allowed to get within Malz's ult range because they had to sell their QSS.
Do ADs need a Zhonyas? Not at all, because there is no mechanic in the game to which Zhonyas is the only effective answer.