Do you mean that the system of communication using the palantiri was a good system. If that is the case I agree.
Or, do you mean that the system worked well as long as Elendil, Isildur, and Anarion were alive. I could go with that. However, they being mortal was something of a flaw.
Or, do you mean that generally it was a good system. As is probably obvious from all of my other posts, I disagree. Looking at the evidence I don't see how it could be said that it was a good system. It collapsed a few decades after its creation. Being able to communicate through the palantiri did not equal control over the under-kings. Gondor was too far away to control properly. It would be exceedingly difficult to launch punitive military expeditions to keep Gondor in line, to say nothing of costly, it was so far away and well blessed with resources and population.
Essentially the King of Gondor was in a position to declare independence whenever he felt like it. Not a good system for keeping the empire together.