Off the top of my head we have The Dickey, Marlins, Tulo, Olerud, Sirotka, Loiza trades are easily among the worst trades this organization have ever done.
This trade was fine. Gurriel had limited value and Moreno is still a question mark. A lot of the defensive side of his game is questionable and his bat was league average this year. It's going to be fun to look back on the Varsho/Moreno trade in 3-4 years and see where stuff sits, I honestly wouldn't be surprised if Varsho puts up 12-14 fWAR in his 4 seasons in Toronto and I'd expected 10-12 for Moreno in his 6 with the Diamondbacks.