Gearbox on enemy blance

ok so creatures…mmm throw some armored ones in that sounds good
maliwan guys…mmm shields, always elemental damage, maybe some armored robots.
guardians, pure shields but lets throw some armor on a few too
bandits…give them everthing…no like everything, give all the bad asses 3 massive health bars and then keep debuffing elemental damage on mayhem mode so then when more than 4 pop up at a time the player just dies…mmm not quite enough…lets throw in some extra purple guys that will just become immune to damage and bug out and STAY immune to damage…that sounds balanced with the other 3 enemy types