To be fair, there was a lot less of TOS than the Berman Era. Three seasons, six movies, and that was it. Berman Trek had to create more because there wasn't a lot already there. (I didn't include TAS because they considered it non-canon).
Another thing too is just how rare there were direct references to other episodes in TOS. After Vulcan worldbuilding, the Klingons, Romulans, and to a far lesser extent the Andorians and Tellarites, that left the Galactic Barrier appearing in 3 episodes, Mudd returning, Pike getting name dropped in "Mirror, Mirror", repeating a method of time travel, and offhand callbacks, like to "A Taste of Armageddon" in "By Any Other Name".
It would have been very cool for TNG to do some "100 years later" follow ups to TOS, but, even then, it's not like the average TNG episode would have a follow up or direct reference, just pivotal ones that established mythology worldbuilding (Klingon, Romulan, Borg, and yes later Cardassians and the Bajorans) or once a season (or less) recurring characters, like Q, Lore, or Lwaxana Troi. If "Sarek" had to be the one that made it, I'd take following up "Journey to Babel" with Mark Leonard's performance over something plot related that no doubt could be a topic for a TNG novel or comic.
Contrast this with STARGATE SG-1, where over the span of 10 seasons, almost every single episode has some kind of continuity call back. Or even THE X-FILES, with their pure mythology, tangentially related mythology, and stand alone MOTW episodes.
BTW, to Lord Garth, I hope your job search process is going well.
