I grew up with TNG and only saw TOS retroactively, hearing all the tropes about Kirk and his exploits. But you know what? Kirk didn't get half as much ass as Riker. Kirk was just seen on camera a bit more often with his stuff. Riker's is all implied and from dialogue about his personal life.
The Tylered V'oq vs. Hippie V'oq fight should have gotten a deeper spin. The whole V'oq arc was left behind and not concluded in a satisfactory way.
I somehow liked the Disco Klingons, but the hate they got made them disappear from the show almost instantly. Q'rell was taken along, but the whole Klingon war was handled offscreen.