Why did it absolutely need to become a unique passive? If people were giving up the benefits of other items for the sake of better heals, that seemed to be an apt, reasonable decision on their part that didn't hurt anyone else.
When I played Soraka, my build would always be 
, and it got me quite a lot of S's back in the day. Because it worked.
Crett3 votes 
never forget
Ok sure but why1 votesrest in peace good build
Chamuel851 votesPerhaps it works too well. Especially with someone like Karma who could give an entire team 800 HP shields on low cooldown without Ardent Censor.
Ok sure but why1 votesYeah, but then she gave up the power of a Luden's Echo, or a tanky item to keep herself alive. It was her decision to be a team player.
Chamuel852 votesWhy is Luden's proc unique? Why can't I just have 5 of them? I mean I traded off the power of any other item to get 5 Luden's Echo. I mean you're giving up any MR pen, Deathcap, Rylai's slow, RoA's tankiness. etc etc. In that case, why should any passive be unique at all?
Ok sure but why1 votesThen why is the less crit damage from Randuin's Omen not a unique passive? Why is the bonus base damage from the Sterak's Gage not a unique passive? Those two items' perks aren't unique because they don't give anything special. They just boost an effect. The Ardent Censer's passive is like that. It only boosts an effect, and that's what it did well. The only reason no one is bitching about the Omen or the Gage is that hardly anyone ever tried stacking those.
Chamuel851 votesBecause oddly enough, balance on passives is a case by case basis.
Ok sure but why1 votesAnd imagine if someone did get six Luden's Echoes, and all six passives would work. That's cool, sure. But that person would have NO cooldown reduction, NO mana/mana regan, NO health, no nothing. Just 600 AP and some movement speed, and the occasional Q that did an extra 960 damage. If someone likes that big poke, then they should be willing to give up all of their other necessities to attain it.
Rımuru Tempest1 votesu can still build + 
, its still a 30% Boost to heal and Shield power, you also can get a 
, 
, 
AND boots of your choice. its still a good build for healing as Sona/Soraka .
i also like to use the icons tho.
Hyperiön1 votesArdent and Mikaels no longer stay, they have the same unique passive.
Ok sure but why1 votesWell, the update does say they can still stack with each other.
Hyperiön1 votesOh okay, must have missed that part.
Erockandroll1 votesOh okay, must have missed that part.
The trick is named passives.
Unnamed passives won't stack from the same item, but will stack from different items. You could build 
and get 30% CDR, even though the 10% CDR on each item is unique.
But named unique passives like Spellblade, and Immolate, won't stack with other passive that bear the same name.