Why does Illaoi not have a cap for her heal from her Q passive?

Illaoi can 1v5 most team comps with 5 Warmog's Armor and a Spirit Visage, and since Warmog's now gives 10% cooldown reduction, she can do it easier. Even if it's a 1v3, she can use Test of Spirit on someone, then use Leap of Faith. If she has one tentacle on the wall, then she will have 5 tentacles after her ult. If each tentacle hits at least 2 people, then she will have a 50% max health heal which will be increased by Spirit Visage. That's just when she uses Harsh Lesson once, and since her ult puts that ability on 2 second cooldown she can keep spamming it and with each tentacle doing insane damage she is basically unkillable. She needs to have a cap to her healing done just like Darius does on his Q. If she manages to get a full team ult, plus Test of Spirit, and each tentacle hits at least 3 people, she will heal for 90% of her max health. With that kind of healing, she doesn't even need to be tanky. She can just roll all over you with no negative effect to it. And if she does build tanky, she can walk in and smack you around and you can't kill her even if she misses half her shots. I understand that the balancing is based around Platinum level, but this isn't even fair for lower elo players. Plus with so many champions being broken with the new Bloodrazor, and the fact that we get more and more champions every year, but still only have 3 bans per team, it basically just makes you chose who will kill you.