Reasons for cross-voice limitations?

[Urs Liska]

Hi,

this has been discussed numerous times, but I think I'll have to bring 
it up once more: the limitations that slurs, dynamics and other spanners 
can't cross voice borders. This limitation is a major inconvenience for 
users: New users are regularly confused, using hidden voices to work 
around the limitation is actually an ugly workaround, and it's not 
acceptable to be forced to use such workarounds for reasonably common 
things. And now I've come to suffer from an issue where this limitation 
is a real PITA: the partcombiner.

I find it quite obscure to tame the partcombiner to do its work anyway 
(for example, when you're facing an issue you don't have a real way to 
tell what "mode" it currently is in because the last switch could have 
happened about anywhere, and in any of the voices taking part in the 
combination). But I've come to the conclusion that very often the 
partcombiner has to make ugly choices because it's bound to keep voice 
contexts alive during the whole spanners. Often it remains in 
partcombineApart mode for ridiculously long ranges, just because a slur 
has to be closed in the same voice as it has begun. And this kind of 
issue is usually sooo awkward to solve because you might end up 
inserting a hidden voice to achieve the slurring but have to restrict 
that to the partcombined staff while not using it for individual part 
printing etc.

So I want to bring that up once more: Why do we still have this 
limitation? Is it an inherent problem that can't be fixed, is it just 
because noone cared (or had the chance) to fix it, or is it "only" 
because we didn't explicitly think about the right way to deal with it 
semantically and with regard to syntax?
I mean, I can't imagine it makes a serious difference when it comes to 
*engrave* a slur. It may make a difference for managing and maintaining 
contexts, but just as it is possible to add a hidden voice to accomplish 
a cross-voice item it should be possible to create a built-in solution 
for that.

This wouldn't fix the partcombiner limitations, but it would at least 
make it possible to think about improvements.

Any ideas?
Urs, frustrated ...