Taekwondo Pyong-an patterns are exactly the same as the Shotokan Heian patterns. For example, Taekwondo Bal-sek pattern is the same as Shotokan Bassai pattern, Chul-gi is the same as Tekki, and Kong-san-koon is the same as Kanku. Palgwe Taekwondo patterns are also similar to Heian patterns.
Watch these classic Shotokan kata and look for similarities with traditional Taekwondo patterns.
Although the ITF, with its Shotokan influenced patterns, was popular around the world, the WTF gained control of Taekwondo within Korea. In later years, when Korea won the bid to host the Olympics, the WTF was chosen to lead the effort to include Taekwondo an Olympic demonstration sport. Korea, through the WTF, wanted to purge Shotokan 's influence from Taekwondo so it would only reflect Korea's martial arts history. As a result of the effort, they developed a set of strictly Korean patterns they called Taegeuk (which is the name of South Korea's national flag).
The essence of Taekwondo is poorly reflected in any of the commonly recognized ITF or WTF Taekwondo forms patterns, whether they are Pinans, Chon-ji, Palgue, or Taegeuk. Their techniques are mostly an arbitrary series of movements that do not have many variations of kicking or punching techniques that do not reflect skill level of their assigned ranks. They are not particularly exciting to watch or perform, do not demonstrate any aspect of skill that is particular to Taekwondo, are nearly devoid of technical challenge, lack roots specific to Taekwondo, and are considered boring by most practitioners.