A 2-3 zone will stopp the 3 Skill-LI Guards. Like it should. But because the users of BB have another image of LI than the creators, everyone shouts that the 2-3 is broken. But it isn't, it's just that we aren't playing a "true" LI.
And that's the point of adjusting the balance, and why there's a good case to be made for altering 2-3: because no matter how perfectly the algorithm works in a test scenario, once you release the game to the world, you need to balance it for the real-world gameplay.