Seeing as how this is the first new iteration of the March update, there's bound to be some bugs and things to iron out and fine tune for sure.
But I agree it would be nice if the side bar could be toggled to expand or collapse into a slim bar like in the iteration pre-March when you could collapse the left bar into just the episode thumbnails.
I also agree with the comment section, though I guess 95% of comments never reach a length that it's too troublesome. But it does get to be a chore looking through a comment chain of replies since it reduces the space even further. like this