I'm not 100% sure of this, but for the most part I think the planes themselves haven't changed much from edition to edition, though the cosmology of how they're related/positioned relative to each other and how you get from here to there has changed through the editions.
I don't know about the quality of any outer planes content specifically, but I know 4e had some good cosmology supplements in general- they had a really good Feywild book.