TBC was initially designed to enhance the Classic game

It's too easy to look at it through a retail lens. There isn't a "chronological or overarching narrative" to the quests for expansions. The majority of WOW Classic TBC Gold things are located within their own zones. There was not a lot of elaborate story telling back when. In 68, you have the option to pick between Shadowmoon and Netherstorm. But neither does anything to include the other. There's no definitive story line. For raids, you'll prefer to go to Kara > Gruul's Magtheridon> Tempest Keep/Sepernt Shrines (again it's not in an orderly sequence), Hyjal Black Temple, Sunwell. ZA is fun and it exists. But, as with all Trolls, it's not "in" anywhere.

TBC was initially designed to enhance the Classic game. The use of a TBC server will allow you to access to the majority of Classic content, even though it's no longer in use. The servers are now considered distinct games that benefit players who like the classic version of the game.

Wow, classic is gone. I would recommend TBC to anyone looking for vanilla. Are you a new player? If yes, I recommend that you look into the retail option instead. It's more refined and buy WOW TBC Classic Gold has many enhancements to your quality of life.