I agree with everyone that prestiging needs a bit of a rework since right now the only people that farm prestiges are average and easy xp normal accounts due to how easy it is for both of them. The boss definitely needs a loot table rework since its just useless. Not sure how the whole "each prestige unlocks a new boss" would be a good idea since, like I said before, average and easy xp would have no effort in getting to those prestige levels. I would say an overall loot table rework with each prestige giving you bonus droprate at the boss. In that case, easy xp accounts would get the bonus droprate faster, but heroic accounts would end up with the best droprate since they have a better base droprate.
The barrows totems definitely should not drop from the brothers on top of the hills, and I think getting a totem for every daily is just too easy. Maybe an overall increase in totem droprate but adding it to daily event would make malevolent easy.
The sponsor idea I think its good, but probably would be best to not make a bunch of infinite resources no matter what your donation amount is. Maybe an infinite magic tree, and a cool cosmetic aura, but certainly not infinite runite and ancient ore etc.