There was some debate on that when they decided to include LibreOffice on the desktop LiveCD. Their reasoning is that most people put it on a USB drive anyway, and don't burn it to a CD.
I really don't agree with their decision to make it larger than a standard CD, but nothing I can do to change it
I believe the Xfce spin still fits on a CD, though.
Edit:
You could file a bug in bugzilla, but it would probably get closed as not a bug since it was by design, but it would at least let them know that people do still use CD's