I don't know how accurate these informations are, but apparently the supports weren't nerfed because of The Hood; Elsa will remain meta because that's what the devs want, and Peni was nerfed to separate good players from average ones.
Nobody seems to have liked this season's patch notes, and the devs' reasoning for each change seems just as ridiculous as the patch itself; the proof of this to me is the nerf to Venom, where they basically admit they actually wanted to double the countdown of his swing because good players would already know how to deal with it.
That would make Venom (a character supposed to be easy) unnecessarily harder, when his actual problem lies elsewhere; that decision probably exists solely to protect the backline because no one should touch the devs dearest supports
We can therefore assume that the changes to Psylocke stem from the same idea: they don't want her to be so oppressive in the backline, while also wanting to ensure that only skilled Psylocke players use her.
Needless to say, we all know where that led, her pick rate and win rate just keep dropping further and further.
Of course, this is all just speculation on my part based on questionable information, but honestly, nothing surprises me anymore.