Why new Banshees is a bad replacement for Abyssal

You guys are the ones who kept nerfing abyssal scepter over time, so naturally, you must know that the only reason you purchase it is because you really need an MR item and it's the only ap item that gives MR. You don't buy it for the damage. So, why are you trying to replace the mid lane magic resist item with an item that not only gives less less MR, but gives even less damage? And don't try to make an argument for the banshees veil passive compensating. That item stopped being built a long time ago when you guys doubled the refresh time on the passive. The only reason people still buy it is because it gives the most MR out of any item in the game.

I don't know if you guys realized, but mid laners don't take a full set of magic resist glyphs almost ever. 10% cdr + either mr or ap is what's most common. So when you reduce the magic resist of the mid laner magic resist item, you in-turn are going to inspire people to build liandris every single game, because there's basically no point in building void staff. Locket doesn't give aura MR anymore. Mid laners don't really take MR glyphs. ADC's don't incorporate MR into their builds that often, and when they do, it's normally a 4th or 5th item Scimitar or GA. (EDIT: I just realized that GA is no longer going to give magic resist. So even more reason to not ever build void staff, I guess)

Can you guys (Riot) explain to me what the point of building a void staff will be if you go about making changes like these?