Sad news, as Deep Silver originally confirmed to me Homefront: The Revolution was going to be a day-1 release, now they are not saying when.
They did confirm it's still in development:
Sadly they didn't answer the question directly:
It might still come out at release, but their language "in development" and Steam only having a Windows icon to me says it will be a delayed release. A real shame, as it was one of the titles I have been looking forward to the most.
Same day releases are really important to Linux & SteamOS. It's still great it's coming.