I didn't mind the fact that the supporting characters took a back seat, and I was fine with the resolution given where everything was in the episode immediately preceding. But I was expecting that there would be a spectacular final musical number, and the Eleventh Hour medley wasn't that for me. Even a payoff of the theme song (which I hated more and more as the season continued) could have worked, but it was essentially just the same joke with different words week after week and it didn't resonate with the arc of the plot the way the 2nd and 3rd season themes did.
I think the finale could have been better if the season had been more tightly-structured. I'm not saying that they should have told only the most essential parts of the story -- just that it felt like they picked up and put down threads and ignored some of them for too long when they should have had some background presence even when they weren't foreground. I think I would have appreciated Rebecca's decision to work in musical theatre more if we had seen consistent progress throughout all of the episodes starting from theatre games with the women she was helping in prison, to seeing her half-brother's interest in performing, to working on the amateur Elliott Ellison revue, to parodying the Elliott Ellison songs, to the final realization. We got some of it but it was disconnected.
I'm sure they intentionally left Greg and Nathaniel single to give hope to shippers. And I thought the Where Are They Now worked to make sure that we didn't have to grieve for Josh, Greg, and Nathaniel's disappointment.
My biggest disappointment was the lack of Naomi, because I wanted her to have a place in Rebecca's life within appropriate limits. But I am probably thinking of season 1 Naomi -- season 4 Naomi was perhaps all or nothing and they went with nothing.
Was glum-looking spaced-out Rebecca supposed to be retreating into imaginary musical theatre in her imaginary futures?
I started watching the concert but have put it aside, don't know if I am enjoying it enough to continue. I feel more like rewatching the show versions of some songs I haven't thought about recently.