proposed architecture change for theme customization

[Glen Mazza]

Hi Team, I noticed our theme and theme stylesheet customization pages 
offer two tabs--standard and mobile--for users to do their 
modifications, even if they're not using a dual-theme approach (i.e., 
using a single responsive theme good for all or an unresponsive theme 
where the blogger doesn't care how it looks on a smartphone.)  It 
appears with the current design the moment the user decides to make a 
customization he'll now need to copy and maintain the modifications into 
both the mobile and standard versions of the file, instead of just 
having one file to work with, messy and unpleasant for those expecting 
to maintain just one set for their theme.

What I would like to do is for the theme descriptor file (theme.xml), to 
add a new <dualTheme/> element which will default to false if missing.  
All of our themes except basic-mobile will have a dualTheme of false.  
If the value of this element is "true", the blogger will see two 
tabs--standard and mobile--for his theme & stylesheet customization 
pages.  If the value of this element is "false", the user will only see 
the standard tab, so he'll have only one file to customize instead of 
two.  How does that sound?

I think it would be good to get this fix in before we release 5.1 
because it will be more difficult to fix in 5.1.1 when we would have to 
take backward compatibility into account.

Regards,
Glen