I was just wondering what the appeal of the Original Series is to you in particular...
I've spoken to many fans, authors and publishers who adore the Kirk era whether adding new lore to it or simply revelling in what was had on-screen.
Some of those acolytes were around at the time that TOS was first released and others when TOS and it's associated films were cracking on a bit but the only option as TNG hadn't yet come to the fore, others because regardless of what was on television TOS was their first perhaps introduced via a relative. So for many it was formative.
My first ever Star Trek of any fruit was TOS; Galileo Seven and Balance of Terror. Those episodes showed me that people dared to dream and to show those visions on the screen to share and to entertain. Sure, a few weeks later I saw a lot of TNG but the die was already cast and so for me putting aside the orgasmic c.g.i. of the Dominion war scenes in DS9, TOS reigns supreme.