Reasons being listed here:
Stasis harpoons and crowd control affect him far too much. He is a slow ball already CC is just a salt in to the wound.
Tongue grab is a disfunctional hard to hit and most of the time doesnt work like its supposed to:
Hunters who are sitting on a ledge can always just step back for a second because if the tongue doesnt have 100% clear line of sight on the hunter then it will always miss.
The angle in which hunters fly towards you after the tongue is bad because most of the time hunters are hitting roofs, trees and other shitty objects stopping their travel all together add to this the fact that hunters can slightly affect the angle in which they fly and you have a pile of crap that barely ever works and rarely if ever gives you the advantage you sorely need.
Well now Rock Wall has the obvious problems of walls not showing up but also the fact that its rarely if EVER worth putting more then one point in to it means that it needs drastic changes in its functionality. Level 3 Rockwall and to a lesser extent level 2 rock wall are pointless investments because they dont increase the duration of the wall they just give you more broken wall that doesnt actually benefit you in any way.
The ideal way to use rock wall is to place 1 point in to it and then Tongue grab someone towards you away from the enemy team throw up a stage 1 wall and then pounce the said target before the wall goes down, and if they have Cabot then it might as well completely have been a wasted opportunity.
For all of its issues the wall would be better if the amount of points you stuck in it would actually increase the duration of the wall by 2 seconds per point meaning you could completely isolate someone and actually have the potential to down them properly.
As is you can pop a lava bomb then use a fissure and a second or two later watch as your so called “burst” fails to take the said hunter down and the Wall comes crashing down and the hunters are on your ass again.
Fissure is extremely easy to dodge currently for what its supposed to give Behemoth. In a sense I would say Fissure is supposed to be Behemoths Rock Throw but without the actual burst to let you outdamage the shields and healing that hunters are currently doing.
The size of the Fissure has to be increasable by each point you invest in it and it has to travel faster then it currently does OR the windup needs to go away, I would say the former is the better option since behemoths weakspot niche is to show it during his attacks.
Add to the appalingly easy dodging to the Fissure and the fact that it can go under maps means it is extremely unreliable and more often then not a missed opportunity to do damage rather then an actually threathening attack. Especially considering how little it does at the end of the day.
Lava bomb is most likely the best weapon in behemoths arsenal. You can use it to deny areas create some slight burst and dot damage also you can shove hunters off pillars and objects with it like nobodys business however the problem lies in its damage. It doesnt have enough burst and the dot is far too ignorable. It is extremely easy to outheal and again to dodge even.
Behemoth is slow fat and extremely unwieldy to the point where he is cheesed to death by every single hunter with some brain in them.
The huge windups, lack of proper control, buggy skills, slow movement and terrible relay fighting capability means that Behemoth is constantly being outdone by any competent team. He has no advantages.
He is a fat punching bag that doesnt do anything worth mentioning especially comparing to other far more reliable, faster and smooth monsters like Kraken, Wraith or even Goliath despite his buggy traversal.
tl;dr: Behemoths ability to traverse out of ball and inside the ball must be improved, his skills need to give more for the points invested in them and his bugs have to be sorted out asap or else he will eternally remain in the garbage bin.
P.S: I am talking about the PC version of the game here.