So if it is in shooting mode it takes significantly reduced damage from krak and doesn't even get staggered out of it. This had got to go. It is the most tanky "extremis" enemy that somehow magically gets stronger armor just because it crouches down a little. 

Either lower its health or fix krak not doing the same damage as it does to every other extremis/not staggering it. This enemy already spams a somehow even more BS version of spore mines. (acid spore mines, yay now when you dodge the mines you still get damaged because of the puddles they leave behind for 10 seconds. So much fun)

heck while it is in its way too fast running mode it seems to also take less damage from krak and not get staggered. 

This enemy is so broken, fix your shit Saber.

Yeah, something is fishy about this Biovore chap. Last time I used 2 Krak grenades on him while he was not burrowed. Only then he could be finished (Ruthless and higher difficulties). White burrowed = no chance. Also, shooting his cannon while burrowed seems to not help in most cases. Yesterday I shot at least 10 rounds from Last fusil in it and nothing. Also the sniper perk for 50% damage in block stances is not working on him correctly. Maybe it is bugged or there are situations where it will be bugged. Don't know. Sometimes he goes down easily, sometimes just nothing works as intended.

Only melta bomb and melta weapons can do the job nicely + the plasma weapons are good, but he should get some tweaks for sure. 

Not to mention the melee combat with it. There is no combat flow, which means, he can mix up his attacks whenever. That melee bomb attack is the worst. He can pull it out anytime. Acting more like the lictor, but you have less time or no time to react to his orange attacks.