To get right to the point I cheapest Maplestory 2 Mesos propose ramping up the difficulty up a bit like (might be a very long list) to get Zakum, the present normal zakum should become easy zakum, the present chaos zakum gets normal zakum, and create a whole new considerably harder chaos zakum. Same for horntail create the present norm horntail simple honrtail, the current chaos horntail normal, and make a whole new tougher chaos horntail.
For the origin abyss bosses there current chaos forms ought to be normal and make a completely new tougher chaos for them. For hilla her hard form should be normal and make a new tough form for her. For Von Leon his normal form should be simple and create a new harder normal type. For Pink bean his current chaos form ought to become regular and create a more tougher chaos form due to him. There are probably more supervisors but I can not remember them right now but I believe you get the point. The problem for the current supervisors are way to easy and lost their pleasure of being challenging, and I expect you guys give this some consideration.
Well Zakum just got revamped and people are complaining about the new chaos zakum being too challenging now (its not, it just takes you buy Maplestory Mesos to actually fight a boss instead of stand in 1 place, the lag is a larger problem than zakum).But no I do not agree. I don't think you've fought most of the bosses that you've listed out. Horntail is actually in the very best location for bosses right now since his falls are almost perfectly aligned with his difficulty, which is not accurate for almost any other boss in the game right now.
Yes he is harder, but he is being revamped this season I think so we might need to wait and see what happens with that. VonKittybutt could be made more difficult, but why? I really don't see the purpose. We need some lesser leveled, easier bosses for lower leveled players to enjoy fighting. VL is a really fantastic boss fight, very well designed. I do not support placing that boss fight out of reach of players because you believe he is too simple.