The episode didn't show us anything interesting that we didn't already know about Kirk
It didn't really have to. It was more of an exploration of the general concept of missing time, similar to what prisoners experience after decades of incarceration, or Tom Hanks being marooned in Castaway, only much much longer.
I guess what I thought of most wasn't so much David Bowman as the guy in Interstellar that had to sit around waiting for years to link up with the other ship due to time-dilation.