For me, I think that the only abilities with having on defense are the DT stack (Double or nothing, el toro, BOGO), and then this year they made it way harder to get user picks so I would use pick artist on anybody I could.
For offense, I use Spincycle on big players, and all my other AP on my QB(conductor, gunslinger), and then Idetifier on my OL
This year, abilities seem to just be terrible on defense