At the moment we don't have any plans to go into that direction. I remember one other customer asking for this feature.
I can only guess, but it seems that most users who use Google Docs come from Word and they did not use cross referencing there. So they don't really miss it.
Coming from LaTeX this is clearly something that is missing but at the same time also formula typesetting is missing which makes it hard for LaTeX user to switch in the first place.