That again has nothing to do with PvP which is what you keep bringing up, why fifth column was an obvious misuse of game mechanics, it was an obvious flaw in the design of the mechanic that allowed people to do something that made no lorewise or gameplay sense.
Claiming otherwise is folly, there was nothing illegal in the action itself, people used a mechanic that frontier made available, but it was pretty obvious that it was not an intended mechanism, because it was very obviously working against the best of the faction, something that lets say the faction leaders had a dedicated GM controlling them, would quickly be spottet and the people doing it kicked out.
But to begin with it was one of the ways to interact, correct? Just as you could blow up opposition fortifiers you might also nick their stuff for profit that leapfrogged that of NPCs. Now most of that is worthless vestigial trash.
It was a shame, as it was a useful tool for controlled turmoils, one that my old Power used very well.
We all speak from what we know, but you are not presenting anything about 'why' it would be good, you are saying "it would be good" and "this is better" but not presenting any real 'why' behind it, why would open only be better? the ONLY difference it would make it maybe increasing the chance of finding players and attacking them.
And as already established that is a poor way to do Powerplay, the mechanics simply do not back that up.
For the last 15 pages of responses I've outlined the 'why' as best I can. Thanks for reading them so closely.