For the Curses deck, since we're in white and not required to stick with Modern anyway, I'd ditch Seal of Cleansing in favor of a much more efficient solution - Null Chamber, naming Witchbane Orb. Now it can't be played to destroy all the Curses you've managed to lay. Also the obvious issue with any deck built around Curse of Misfortunes, Curse of Thirst, and Bitterheart Witch would obviously be that they all have CMC 5, so I would have stayed away from adding other Curses that also have the same cost (Echoes is particularly cut-worthy since it has the potential to do literally nothing; Death's Hold is forgivable since there's really no substitute for its potency as a control tool, but I would also drop Bloodletting in favor of more Pierced Hearts, even if this skips a nice Misfortunes combo).In other news "hug the Tree" is now my favorite Magic-related phrase of all time.
As far as the benefit of the rest of Magic is concerned, gold cards in Legends were executed perfectly. They got all the excitement a designer could hope out of a splashy new mechanic without using up any of the valuable design space. Truly amazing.
--Aaron Forsythe's Random Card Comment on Kei Takahashi