There are few people running Windows AD who are going to view this as their next step, largely because they've already become used to running those Windows boxes.
For groups who aren't fully invested in AD, or need compatibility with those who are, this is a major win.
Microsoft AD is the ONLY reason many companies (Apple shops included) have Microsoft servers. People cannot imagine how disruptive is a fully operational Samba 4.0 AD for Microsoft. (like a fully operational space station with a planet destroying laser :p)
How are the GUIs for Samba 4.0 AD features? I usually prefer nice configuration files, but the Windows Server features were very easy to learn. Another nice thing about Windows Server, updates are "free" after a high up-front cost.
Not immediately, but the thing that people can set up and try and say "yeah, sure, problem solved" has a funny way of making it's way into the rack. Whether it does or doesn't in a specific case usually just comes down to whether the one supporting it likes Vi, Emacs, or Word.
Google Docs has no relation to OpenOffice iirc. The word processor came from writely and the spreadsheets was some other company's source code, the rest was just extensions on that.
For groups who aren't fully invested in AD, or need compatibility with those who are, this is a major win.