I do agree with you on one point: They really shouldn't be nerfing tank items if they're changing glass cannons so much. Not yet. We need to see how these NEW itemizations interact with and counter RECENT item additions. Tanks have been declared a bit broken lately. But a tank nerf may be totally unnecessary with all these new glass cannon avenues incoming.
However, your assessment of the changes feels too deja vu to me, and not in a good way. Honestly, I see people rage out at minor changes just as much as they rage out about HUGE changes like this one. I think at a certain point Rito said, "screw it, we'll do what we want."
First, Riot introduced some major fighter-tank itemizations that are amazing but broken at times, and some people were pissed about that. But, ultimately, it made fighters more entertaining to play. NOT because fighters were suddenly broken, but because fighters had a larger set of effective options available to them. Now, Riot introduces a bunch of glass cannon itemizations that are amazing, but likely broken, and other people are pissed about that. Every time Riot introduces something cool and empowering, but, as a result, PROBABLY broken at the start, there are plenty of people that are gonna get pissed and say "quit touching my stuff!" Well, it's not your stuff. It's Riot's, and they don't even try to play the game of pleasing everyone.
In the long haul, pleasing everyone all the time is impossible ANYWAY. With small changes, there are ALWAYS people saying "it's too little" and heck, ALSO people saying "it's too much". With large changes, same deal. If game popularity doesn't go down with a change, and the changes ARE cool and empowering, Riot has no reason to fear the inevitable disappointments that will ensue. Ultimately, these changes will likely keep MORE people around, because it opens up cool avenues for certain players. Not EVERY player, because again, Riot can't please every player at once.
Face it. They did this with tanks, mages, and AP fighters recently (luden's, sterak's, rab buffs, deadman's plate, yada yada.) It was bound to happen with ad glass cannons next.
As a side note, some of these items are used on AD fighter tanks as well, so, ironically, we MIGHT be getting slight buffs to AD fighter tanks through these changes (Skarner with the new trinity could be even more annoying, for instance.) That could explain some of the tank nerfs. But maybe I'm reaching here. Tank nerfs do bother me. I've seen enough tanks melted like chocolate on a Summer day in the face of certain ADC's as it is. Doesn't seem like ADC's need a helping hand.
champion with 5 attacks for persecond max and its own built in % max hp damage on the w and 8% current hp damage