I can't prove that they are OP, but equally you can't prove that they are not, it's all down to opinion. In my opinion the burn with Viking Funeral lasts too long and takes you out of the fight for even longer. One of the perks applies to the melee, which is already very strong, and a lot of subclasses don't get great bonuses in those perk trees or the bonuses also apply to the grenade. The trouble is that in elimination especially, and sort of in all 3v3 game modes the enemy is communicating, and all they have to do to turn the match into a 3v2 (for them) is to land a grenade somewhere near you and rush hard whilst you are taking cover, which brings up the other OP thing about the grenade; the fact that it does full damage even if you are right at the edge of the radius, and it is nearly impossible to escape without shadestep, no other grenade does this and also burns you.