As the default builds of nearly every AD champion right now will negate it with lethality, plus more. You're better off just buying HP (but then good luck getting CDR into your build).
EDIT: What I'm trying to insinuate is Mages need another option for armor besides 
. It already has a specific purpose, and if a Mage wants to build more armor, they can't, whereas AD champions have many opportunities to build MR and AD.
Ahristocats6 votesyou're aware that if you had no armor lethality would do even more damage?
Sugar Momma1 votesYou're better off building HP. The Lethality items give significant AD on top of the Lethality so armor has severe dimishing returns unless you can build a ton of it (which mages can't).
Ahristocats1 votesYo friend, build hp if you want to build hp, don't say that zhonya's armor is pointless since it's negated by lethality WHEN ITS THE REVERSE BECAUSE ARMOR NEGATES LETHALITY
and zhonya will still be usefull by its cdr and active that can help you against assassins in teamfight(not in 1v1)
Sugar Momma1 votesI didn't say Zhonya's as an item is useless. It is very useful.
What I mean is if you're building it solely to get armor, it's not that useful. And since it's really mages' only option for armor, that's sorta a problem.
Mages should have another AP/Armor item.
Ahristocats2 votes[{quoted}](name=Sugar Momma,realm=NA,application-id=3ErqAdtq,discussion-id=URKq3AMT,comment-id=,timestamp=2017-02-12T19:09:51.748+0000)
AD champion right now will negate it with lethality,
your words were extremely not true
CancerBasedGod3 votesThat's great, except if you do the math, it is completely wrong...
ZephyrDrake3 votes[{quoted}](name=Sugar Momma,realm=NA,application-id=3ErqAdtq,discussion-id=URKq3AMT,comment-id=00030000,timestamp=2017-02-12T19:14:36.176+0000)
You're better off building HP. The Lethality items give significant AD on top of the Lethality so armor has severe dimishing returns unless you can build a ton of it (which mages can't).
enjoy receiving close to true damage then to the point your HP will mean nothing at all. Sorry but you are so wrong it's not even funny. Zhonya's actually completely negates the lethality of every single lethality item they can build at max lvl (minus 5). That way your base armor remains largely untouched and actually helps you survive their attacks more than just stacking HP and wondering why you still die in 2 seconds
Sugar Momma1 votesYou're right; I should have re-phrased my point.
What I'm trying to say is I think mages should have another AP/Armor item. It feels kinda bad your only option is Zhonya's which already has a specific purpose, whereas AD champions get three options for AD/MR: 
Proxy3453 votesMages need like 300 armor to make a difference against a full lethality build that includes 
+
lol Which they don't get anywhere near that amount,thats just from a tank perspective though.
Big Lincoln2 votesYou're better off just buying HP (but then good luck getting CDR into your build).
Is season 7 the era of 
mages?
CancerBasedGod2 votesNot even a little true... The armor will nullify two lethality items at max level... Also if you don't build it a triple lethality opponent will deal true to most mages late.
CancerBasedGod2 votesGreat, downvote the guy who can do simple math instead of raging...
MaeDoSan2 votesNext thing you know we have tank players saying we need to remove last whisper coz it negates armour fckin dumb . The adcs are meant to be the squishy carries that will kill you end game
Meserion2 votesI'd settle for not giving 25% reduced physical damage taken in place of the armor, as it would be a flat reduction that could need be "out-leathalied" or some garbage like that.
Raoul1 voteshmmm maybe they should give it an awesome active effect that would make it a great item even without any stats at all... oh wait...
SrbLud1 votesIt negates 2 lethality items plus you get it for utility mostly.
SoulAced1 votesEven with lethality have a small mount more armor can still help a age because lethality can make you go into negative armor and negative armor makes you take more then 100% of damage. So if you have 68 armor at level 18 (because 68 armor is what Orianna has at level 18 and it is the lowest of all the mages and 3rd lowest in the game) and they have 92.5 lethality at level 18 (which is the highest that any champion can get with runes, masteries and items, but not including abilities) then you will take about 120% physical damage, but if you have you have the 45 bonus armor from Zhonya's to put you at 113 armor and they have 92.5 lethality then you take 82% of physical damage. While it is not much better, it is still better then nothing. Also they thing you most buy Zhonya's for is not the armor and sometimes not even the AP, but for the utility of the Active ability.
Fluffeh1 votesOh yeah, better off buying HP so theyre dealing true damage to you instead!
Nevermind that the active is the vastly more important defensive tool
Or even that seekers armguard is incredibly powerful early into the game that can save your lane phase against talon/zed/etc
MissingKayo1 votesMages don't need more armor.