Buffing 
would have been a good start or rather creating another item to better mitigate crit. In theory, an item that would provide armor, crit reduction, and auto attack mitigation would've been great. Crit ADCs could still make their way to late game but they wouldn't right click their way through everything.
If this didn't work the Infinity Edge change + Zeal item nerfs would have been more warranted.
OtterlyLost3 votesHonestly, they should have buffed Randuins and Frozen Heart. Specifically Frozen Heart; do you know how long its been since I've seen someone build a Frozen Heart? And you know why no one builds a frozen heart? Because it only offers a shitton of mana and a bit of armor and CDR. If they reworked it, maybe to have it build out of a 
and a 
, that way it still has the mana and the AS slow passive. It would lose the CDR but there are a multitude of items that tanks can buy for CDR:
Building Frozen Heart out of Catalyst instead would give it health, which would make it a much better item.
AstroFerrari 2 votesYou're right, it's been quite some time since I've seen anyone build Frozen Heart. The thing Riot doesn't seem to perceive is that Tank items literally aren't fulfilling their intended purpose.
Tahminatrix 1 votesIve been building frozen heart a lot with all the ad teams, its actually hard to get 40% If you are building armor and you just wanna be really tanky.
Why not make it build out of 3 components and just increase the cost...slap an extra ruby crystal into the build.
Or give it a second unique passive that reduces physical damage taken by like 5% But with a twist...it is applied ontop of your armor mitigation
So say you have 100 armor which is 50% resistance , it puts you at 55% resistance.
but if you had way more armor and made it to 75% resistance, it puts you at 80% resistance..thats huge..a 25% physical damage reduction that squishy champions wont ever be able to abuse..
If riot wanted to make tanky champions more tanky without making squishy champions abuse their item selection then this is how its done.
The goal here isn't to fight the true damage and armor pen its to make them both MANDATORY.
Tahminatrix 2 votesI asked for this earlier, we need another item like that because we dont have access to items for teams that are full of champions that rely on crit/aa speed and physical damage. 
2 slots that idk what to do with, 
is eww because its wasted stats on mr and raw stats does not help very much and nobody is gonna have any real burst to waste on the active...(except maybe 
or 
`s first shot with 
If omen was buffed to synergize with thornmail or vice versa then that could be enough on its own... or another item to synergize with all these.
AstroFerrari 1 votesHaving Omen synergize with Thornmail sounds ideal, but I really wonder why Riot is so scared to pull the trigger on a change like that. If we still had IE boosting crit damage, Tanks could actually do their job.
And the Gargoyle plate active is a prime example of Riot being scared to pull the trigger.
AirKingNeo1 votesBuffing Omen? Then we just default back to the Adaptive Helm issue where DPS Mages are allowed to be broken because "an item counters them".