Great discussion.
I really like the rendition in the first post. I would just replace "max" and "min" buttons for volume and velocity since for me everything should be from left to right regarding the strength of some effect.
I haven't noticed if someone mentioned a sorely missing root note autolearn from MIDI keyboard? That's one of the things that I'd find very useful because every time I load a sample I have to change it by hand. Maybe it's been implemented with scripting already?
Automatic finding of zero-crossing points whilst playing a loop would be incredibly useful, as well as automatic finding the top volume points, since they sometimes make better looping choice. I've never seen a sampler with that function [and I love samplers with passion, still have a rack full of them], and it is very useful.
An obvious buttons for changing the samples would be wonderful, too, regardless the up/down key working [in win], because sometimes you don't have a keyboard handy. I do almost everything with MIDI controllers. Well, I'll look up those scripts and assign them to a MIDI CC. :P That's great.
Regarding saving samples, I think there should be an option to save them with a project or not, because sometimes it is needed and sometimes not. It really should be optional and very useful!
Cheers!