Riot hates AD champions
Okay so lets begin, I main top and jungle i play a mix of MOSTLY AD and a few melee AP champs so that is my bias. I'm at a loss as to what magic resist items to buy on a PURE weighted scale of stats lets take the armor items first
These items stats are PHENOMENAL and i build even a or into heavy AP comps for the aoe stats alone.
now my complaints MR items are in my opinion HEAVILY lacking there are 
and 
which are ALWAYS bought in game because they are the seemingly only magic resistance items worth their gold price obviously there are some niche MR items like full tanks get 
which does have a very nice passive but hard to run on a top lane or jungle champion that needs to do damage but has to deal with a strong mid champion. my only other options are 
3200 gold but it least I can get 
for earlier stats or 
at 3700 gold that's such a time consuming item that for the payoff i'm either having to farm the rest of 2015 or try to gank lanes to try and get the gold to deal with their AP threats. THIS ALL BEING SAID I really think there's a HEAVILY preferred item set up for AP casters in this game even WITHOUT DFG (rip) against ad champions and even tanks 
anyone? so that's my little rant
TL;DR I feel ad champions and tanks are missing ALOT of magic Resist items to counterplay the casters right now i'd like an item that if hit with a spell it increases the caster's CD
and 
