I agree maybe its worth to change Special Drops, but simple removing from Loottable, would lead to more Crookarmors and others. Situation is different for new Players and such who play for a while and often. I donated few weeks ago more than 20 Crook Armors and again they fill 2 Pages in my Persistant.
General Developers to do List is Long and this would have in my Opinion only a very low Priority.
I have a complete different Idea how Special, Rune and Setitems drops could work.
You get an inventory Drop like before but instead of an item it drops different Coins.
Bronce for Special Items like Pots of Devine Pennance and others.
Silver for Runes and Crook.
Gold Coin for Setitem.
There shoudl be than a Trader where you can exchange the different coins for a specific Item Roll. Maybe 3 Bronce for Silver and 3 Silver for 1 Gold. All coin should be tradeable at AH, so not cursed or else.
For 1 Bronce you can buy/roll Rare Items Like Special Pots, 1 or 2 Shards, Halrissas Comb, Greater Heroism Gem and so on.
For 1 Silver you could make a Roll for Rune or a Crook or DM Scroll or DM Weapon.
For 1 Gold you can make a Roll for a total random Setitem ( from the whole Setitem list ).
For 5 Gold you could Roll for a Specific Set ( i.e. Roll only for Ftrsetitems )
For 25 Gold you can simple buy a specific Setitem.
But this would be an Economic Changer and giant work for Developers.
All in all, i think Priority is low, others from to do List feels more important, than this.