Amp has been updated since July this year, so I think you are being a little optimistic in expecting an update let alone changes to the UI

I have the current version of it and I find it to be fussy an clumsy. I really don't like the swipe left and right menu at the top to switch between now playing and library. The area to swipe in is too small and jammed up against the status bar. A standard tab bar works far better.

Even if you don't swipe and tap instead you have to put up with a pointless swipe animation.

Everything is too small, I don't want to have to be careful were I tap...

And the now playing screen is just a distaster, as I believe you might say "it makes my eye balls weep". Just show me the album art, the transport controls and a scrollable now and next. I don't need lyrics, links to YouTube, facebook, twitter, email and wikipedia or concert dates. Make it stop !

And on top of all that it hasn't been updated for iOS 4.0, so no quick resumes from the background.