The change to Illaoi's heal is exactly what Juggernauts need

The point of juggernaut the class is to have: High defense--via tank items. High damage-- Via high bases, scalings, and/or true damage.

The reason the class was and often times is broken is not either of those, but the heavy self-healing they have during team fights, without having to spend any gold at all on lifesteal items.

Giving Illaoi's heal a cooldown so that it can only be used during the lane phase or the beginning of a teamfight is exactly how the healing should go for all of the juggernauts. The lane phase is the point where they don't have their defense items and would need the extra sustain. But having great in-kit healing on top of tank items later on is overboard. Their sustain comes from the tank build you're allowed to buy while delivering heavy damage, and should not be in addition to heals that rival support mages'.