I think Ivern is so hard to balance because he's the only support that isn't money-starved.
I think the reason Ivern has such a huge winrate is that he's a support with a jungler's income. Look at Lulu. Every time she was able to solo lane she was oppressive as fuck because she was safe and her utility scaled with income, making her monstrous when she had solo lane income. If Janna or Soraka could solo lane they'd be just as good as Ivern.
Support items are balanced around strong actives and passives because supports can't afford to compete with stats alone. This is a problem with Ivern because he is able to complete more of these support items earlier and get CDR and actives so early that he's difficult to kill and makes his allies difficult to kill.
As long as supports are 3 levels and 5k gold behind, Ivern will be impossible to balance. If we could close the gap a bit we could make support actives/passives slightly weaker and increase the stats. It'd also have the added benefit of redemption and locket not being built in 99.99% of games. When a magic damage carry
is building this combo you know something is wrong with support itemization and income.
you can go find and kill him yourself.

cries in corner