Leaders of the orgs don't want to run around and remind every member about the need to assign cores.
Members don't want their heads busy with that.
So if no one wants to use the feature - just remove it? Limits are fine, but when enforced automatically. It would be totally okay to give an org some cores when a player joins, or remove them, when he's left. You can even add a talent that increases the gain.
Also, limits are far too small. An organization of 5 people can have 60 cores for miners, 10 cores for HQ/Industry and a few dozens of ships and outposts. Taking into account that no people will ever spend any skillpoints on the useless (for them) core assigment talents... after patch they will definitely lose something. And there can be no unnecessary structures.
So it would be very good to have somewhere around 50 cores for person.
P.S. A person should have one primary org, for which his membership adds 50 to core count. Such an org must not include other orgs. A person must not have to train any talents that help ORGANIZATION. The legates are the only exception.