Illaoi is not Juggernauty enough
Well, i've played as Illaoi a ton of times, in fact i've reached maestry 5, and i've found that Illaoi it's one of the less powerfull juggernauts in the game; yeah i know what you are thinking, "But Illaoi is really op with the tentacles and the healing factor", and yeah, that features are really cool, but in a fight she is nothing without the tentacles, "Yeah, but she has the ult to summon tentacles!", yes i know, and it's really cool indeed, but, with a little kait any champ can get out of tentacle range and she is screwed.
Because of that, i have been thinking of some cool features that would be cool to be added in-game; let's get started shall we?
First a modification to the damage of the tentacles themselfs, my suggestion is that the tentacles will have a variation of 50% to 115% depending of how far the target was hit with the abillity, i mean, if you stand really close to the tencale you will get the 50% of the damage it should deal, and if you get hitted with the tip of it you will get an extra 15% of damage, is pretty logical if you think as if it had a whiplike effect.
My next suggestion is to give a bigger range to the "activation" of tentacle hitting when Illaoi uses Harsh Lesson; it would be usefull when trying to use wall tentacles to attack, sometimes you try to use a tentacle to atack and you are just in the limit so the tentacle doesn't attack and the enemy champ is able to run from you.
Also, the Vessels are a bit useless, yes they are auto attacked by tentacles and they summon tentacles too, but that's all they can do, getting a Vessel would be more usefull if you could get extra health from hitting a Vessel or if the abilities used en them had a extra different effect; also, when you get a Vessel and you get her/his soul killed again the curse should reset/stack more than just dealing the ability damage.
Illaoi needs some cc, more than the slow champs get when they become Vessels, i think what it would be cool if Harsh Lesson had a slow too, you are beeing hit with a big ass idol in you head, you at least would get a little dizzy; also the ult should get some cc too, as i was saying in the begining you can easyly get out of her ult, an area of constant slow inside the ult or a mass fear would be great, in fact, using the idea of Vessels getting an extra effect it could be both, a slow for enemy champs and a fear to Vessels.
Thank you for reading, how i said this is only my opinion.[slayer-pantheon-thumbs]
and 
for the aoe slow/mana/cdr/armor/scaling but
is also good.
<3