Pretty sure the Industrial Planning admin I got was a comm directory hire.
Anyway I'd say the colony balance hasn't changed that much. Human admins remain straight-up inferior to alpha cores (and two-skill admins were a net loss on anything but the best colonies). The noticeable nerfs are: alpha cores aren't as good as before (Hypercognition only fractionally replicates the lost skills), and you can't plop an appropriate one-skill admin on a colony that's having stability or accessibility issues at the moment (assuming you couldn't or didn't want to spare the alpha).
As for the reasoning, the way I remember it is that player colony skills (except IP) got yeeted because they just aren't interesting enough to compete with the rest of the tree, and then admins lost theirs as well so they wouldn't have skills the player doesn't.
There have been ideas for making them come back; I think the best one was making all colonies require non-player admins and then they can have access to whatever skills they need.