they dont want 
to build zhonyas and the new AP armor item and proceed to oneshot squishies.
a new AP armor item indirectly buffs AP tanks like 
more than the group the board has been requesting aka the immobile mages.
TL;DR if a new AP armor item comes out, it would still be inferior compared to zhonyas for squishies but much better on AP tanks
Why does everyone forget about zeke's harbinger? I know it isn't the strongest item now, but I don't think it is that bad.
Would it just be states? Who would it effect besides the intended party? Would it cripple the playability of some champions? Would it have an active? Would it have a passive? What is stopping me from taking this bot to just duel the Marksman? What would its particles be? What would it build out of? Is it a melee/Ranged only style weapon? Lots of stuff to consider, would be neat, but ALOT of things to consider, especially since the MR/Armor items ratio in the game is like 1/2
Vlad would not buy 2 ap armor items.
It would make his damage shit. He already needs each of his items specifically for what they provide, passive or active-wise. 
and either 
or
.
If you swap any items, especially with something specifically for tankiness, like spirit visage, it shuts down any pressure you have. Vlads aren't even rushing Zhonya's now because it tanks his damage potential mid-game. They go wota->abyssal->void first. Sometimes even grabbing Rylai's or Deathcap before Zhonya's.
It would have to have an absurdly powerful active/passive on top of a good amount of AP for it to ever be worth buying on Vlad.
