dvcochran
Grandmaster
Taeguek Cipher is a very good read. I am not familiar with the other book.TKD is not my art and have never formally trained it, so I don't know who does what forms. But, there are a couple of books out there that go back to the "original" forms (the actual karate roots) and look at those sequences that were retained and show applications for them. Here are a couple of them.
https://www.amazon.com/Taegeuk-Cipher-Simon-John-Oneill/dp/1409226026
https://www.amazon.com/Chang-Hon-Ta...2528/ref=mt_paperback?_encoding=UTF8&me=&qid=
But, in all honesty. TKD isn't karate. So, trying to put the training paradigm of Okinawan karate (kata is karate, karate is kata) that was taught originally, is not applicable to all martial arts that were later derived from those roots. In the case of TKD, they took great lengths to remove the Japanese roots from their art to make it more Korean. Furthering your argument, you probably could remove them and not lose what "they" (the founders) were trying to accomplish in making it more Korean.
For example, in Kenpo forms were added because other arts had them and lots of people wanted them and wanted to compete in tournaments with them. In Ed Parker's Kenpo, Long 4 and after were specifically designed as tournament forms and applications were secondary. It could be something similar to TKD.