Dying light and Thanatophobia should affect gates opening.
I think that thses two perks should affect gates opening. Since these two perks dont go further 25% action speed debuff, we could add the gates opening action in these perks.
My point is: the opening is very fast considering that a gate can be opened completely while the killer reaches the other one. I don't think it would be OP, since not a lot of survs use wake-up.
Combined with remember me perk, it could be really useful for a killer in the late game without being too much OP since basically, opening a gate takes only 10 seconds... more or less.
It could be useful against SWF who know exactly when the last gen is done so another survivor just goes to a gate and wait until the last gen is done to win the most of the time.
Also, I don't know why dying light still doesn't affect totems cleansing.
(Of course, the dying light debuffs wouldn't affect obsession's action speed for anything, as always)