User defined styles, you can’t add new ones to Google Docs.
User-created templates are such a pain in Google Docs that I would almost consider it a missing feature.
Tab stops that align to the decimal point.
Google Docs feels like using Word 2.0 for Windows 3.1.
You say that like that's a bad thing.
Feature wise Word 2.0 is miles ahead of gdocs. In fact I'd rather use office 95 than the bloatware that came after it.
It's also lightning fast, unlike Google Docs. It's seriously mind-boggling how far we've regressed that we're running Javascript word processors on eight core 3 GHz machines and yet are arguably worse off in terms of performance and UX than we would be on a 486/33 running Word 2.0.
Office 95 was a beautiful thing too. Oh how I miss the no BS interface and the UI consistency of Windows 95 and its applications.
What features are missing?