One side of my mouth: I've considered trying to figure out where in the four-week cycle the imprecatory psalms were removed from. There are some suspiciously random psalm repetitions: Psalm 90 I think? Monday week 4 and somewhere else? It's been a while since I've prayed the new Office so my memory is vague.

Other side of my mouth: I wonder if it's just legitimately harder to pray the imprecatory psalms with the new organization of "no more than three psalms in an Hour". You could bury them pretty easily in the old rite, particularly before the redistribution of the psalms in the early 1900s. Matins is very long, so an imprecatory psalm can be balanced out in a way which is impossible when every psalm has a spotlight shone on it.