Anyways, personally, I like to think of TMP as a sort of series finale. It's closer tonally and chronologically (in that it's set only a couple of years after the 5YM, but it's another ten years till TWOK).
I disagree. TMP is much closer in tone to 2001: A Space Odyssey than TOS, IMO. Except for a couple of lines from Dr. McCoy, humor is nonexistent in TMP. It's missing that essential quality of FUN that always made Star Trek so special to me.
Plus, even though TMP only takes place 2 1/2 years after TOS, all the actors were 10 years older. And, except for George Takei & Nichelle Nichols, they all looked it. It makes it really tough for me to suspend my disbelief, timeline-wise. Fortunately, by the time TWOK rolled around, everyone had the sense to let the fictional timeline catch up with real one, and everyone was playing something close to their actual ages.