Yeah, I think having waveforms in the pattern editor would be a nightmare of clutter and annoying inaccuracy. Upgrading the Sample Editor seems like a much better idea. I also particularly like the idea of having the waveforms display horizontally since that’s what I think most people, including me, are used to.
Envelopes would be great too. I posted a somewhat similar idea a few months ago with a mockup, just so you know how much I approve of such things. 
+1 to all of what Syphus said.