The Music app IS iTunes. They just renamed it and continued from there. I have all of my ripped music in there just like before; in fact, that's the ONLY music I have in my library.

So don't worry! The same trash UI is available to you... except now even worse, thanks to "Liquid Glass" and brain-dead decisions like moving the playback controls from the empty area at the top of the screen into the content-browser area... where they reside on a "transparent" bubble that overlaps other graphics and text.