By the end of the season I would say that I didn't really like it. Season 4 I thought was just great and I really liked all the different ways they used the versatility of animation to tell stories. This season it felt like a poor imitation of that. We spend the start of the season not really doing all that much and by the time we're finally focused on Bojack's pill-fueled dissociations there's not much time left and everything is rushed.
The show had some high points and of course the monologue funeral episode is top notch but as a whole I'd put this season towards the bottom.
I think my biggest problem with the season is that there was way too much Todd and Diane being exactly what Todd and Diane are supposed to be and that drug my feelings of the whole season down quite a bit. I find Princess Caroline and Mr Peanut Butter centric episodes to be so much better since they are just better characters. In fact, now that I'm typing that I realize that we had an episode centered around each of them and then a few that were more side characters than Bojack which means the titular character had less than half the season devoted to him.
That is especially disappointing given that they ended last season with him being a little happy for once in his life; started this season with him talking to Hollyhock and then...... we didn't see her until an episode where he ignored her almost the entire time. They might think it is clever writing to give us hope of Bojack changing and then spend a whole season showing him not change, but to me that just shows that they cannot write him as anything more than Sisyphus-esqe character that will never get the boulder up the hill. I still like the show but unless they can show us that his self-awareness of his problems can lead to actual change than this show is just treading water with the same premise form here to whenever people get sick of it.