I believe part of the plan was to have it still be quite possible to destroy RCs, but make it somewhat harder than it is now.
Harder? Destroying RCs is a slow process, and RCs can be insta-repaired by paying to enlarge them. Meanwhile, that kind of looting does basically no collateral damage whatsoever. Unless you know you will fight a very long war of attrition, targetting RCs is rarely a viable strategy as it is now.
Well, sure, if you're thinking about disabling one RC.
But what if you could send your looting force through their lands and disable 80% of their RCs for a week?
If you have the capacity to waltz through the enemy's lands and reach 80% of their RCs before needing to refit/retreat, then you can likely just waltz into the enemy capital and get it over with.
Most realms' fortified cities are where the find both the most centres, and the largest centres. You will typically not be able to target these centres until you basically won the war. The loss of the ability to recruit from the other RCs is mostly felt long-term, so you'd need to be able to consistently shut them down on a regular basis.
Some realms do have poor RC selection in their fortified locations, though, which would make them much more vulnerable to this kind of thing.
Overall, it'd depend on the ratio of how much time it takes to shut down an RC and much time the effect would last.
If it was easy, our looting army would probably have used the temporary one while the main army used the permanent one, given how the looting army was way too small to hope being able to destroy RCs by itself.
