I noticed some 'instruments' have elements that don't cover each others range.
 
In such cases shouldn't it only play the union of those ranges? (or have an option ... or be made more obvious?)
Or else, when going beyond the common range (union) you're only getting a partial playback of the intended sound (only the elements which work on that note). OK - I guess it could be just a support element for that part of the full 'instrument' range (?)
 
I suggest that this should also represented graphically on the 'preview ribbon' at the bottom of the interface by e.g, opaque colored block(s) (not just on the individual element sample keyboard display - which, as it happens, appears to be showing the incorrect range in light blue anyway(?)).
 
Take Pianos - Cinematic Piano 2 for instance, (this one actually sounds OK on the outliers as it's more of a choir suppoting the sound)
Element 1 - Mellotron Choir Tape - has a range of G3-F6
Elements 2-4 - extend somewhat further
The Element OSC/SMP keyboard shows a low E to high D range
 
More pronounced is say e.g, on Pattern Synth - Lots of Strings. Between B3/C4 it sounds like a different instrument - with 4 of it's 6 elements dropped. Again an octave lower when it drops to a single element.
 
Hey - the sounds are still cool and why don't I just stick to the ranges where I like the sound, all elements or not(?) Well - perhaps it's not obvious ... and should be?

I can think think of times when this is desirable, say playing a split keyboard with a bass sound or sounds in the left hand and accompaniment sounds in the right. 

Kamikaze
I can think think of times when this is desirable, say playing a split keyboard with a bass sound or sounds in the left hand and accompaniment sounds in the right. 

Yeah - fair call on that Kamikaze ... 
 
Although again - perhaps that should be made obvious by representation on the preview ribbon
and
It may not be the case with non-split instruments.

I kind of agree, but the ribbon is tiny. The Ranges are set in two places too, in the Perform Section Bottom right) and when you load in the SFZ file it's indication in the multisample Keyboard
Have you seen my Colours request in Features. I'm trying to think of a way it coul be applied to the ribbon, but all I can think is with a bar for each element above the ribbon showing the range. But would mean expanded the GUI and seeing that the Gui has 2  sizes (Perform (top left) and Edit), and can see resistance to that approach, which I get.
 
 
 

So the Perform (Browser/Instrument) GUI is smaller than the Edit (Mixer/Options) GUI. There have been calls for Browers to be bigger so more things can bee seen in the list an less scrolling. If you make it bigger, to be the same size as Instrument, it would be mean Instrument has a space to fill. It could then have a bar for each Element showing its rang above the Ribbon, or even 6 ribbons one for each Element.

No I hadn't seen you color code request.
 
Despite the small size of the ribbon you could show it a union/outliers/splits e.g,

 
Or make the ribbon bigger or even a more 'realistic' keyboard. You'd need 2 or 3 pixels x 6 to represent full element ranges in a line form, above or below the strip.
 
 
 

http://forum.cakewalk.com/Rapture-Pro-Colour-code-the-elements-m3221362.aspx#3221362
 
With 6 elements, I'm not sure how you could tell from your mock up where are where. It looks like just 3 in there.
With horizontal bars above the ribbon you'd see from the Instrument Page exactly what was going on. Seems the instrument page is meant for performing from, so woud be the right page for needing to know what keys to use.

On the small ribbon mock up I was just trying to show
 
Blue - Union - All elements
Orange - Outliers - Some elements
Red - Split Keys
 
Also I'm running a 1920x1080 display and even at that fairly high resolution it's bigger and more visible/readable than the inline image above. Here's a mock for scale ... or save and view full size.

 
Oh yes - I've had a hack at my Expansion Pack resource image too - works well :).
 

That aproach would save modifying the GUI Size, thia wouldn't but would show more detail, but allow Browser to be expanded
(my MS Paint skills aren't as pretty)
In my thread regards colours, these would match the element colours instead of being white

 

How do you mean 'split keys
If you had 3 element on the first hlaf of the keyboard and 3 elements on the second half, How would that look?
(I just took a screen print)