When Suyin assures the guests that Zaofu is the safest place in the world, a later chapter revealed that Aiwei let Zaheer and his team to infiltrate the city to capture Korra. This is similar when Joo Dee told Aang and his friends about Ba Sing Se's protection from the Fire Nation.
I guess I see where you are drawing the parallel, but I would not say that is a direct repeat. Suyin says this because she actually believes it and stands by her city and it's protective measures. Joo Dee was only saying it because she was brainwashed by the Dai Lee. Plus Zaheer's main intention was to capture Korra and get out unseen. Azula was in Ba Sing Se to take over the entire city, capturing/killing Aang was a big part, no doubt, but she would still have been successful if Aang had never returned from being with Guru Patik. Similar in some ways, but vastly different in others.