This question has come up quite a few times recently… I can categorically state that you should NOT consider Roo a viable approach for developing Surf applications. As Jeff said this was worked on by Dr. Yong Qu who hasn't worked for the company for a long time and there has been no development on the Roo development tooling since he left.
I haven't used STS recently but I'm not sure why it would not continue to support Surf development because of a FreeMarker dependency. Ultimately a FreeMarker file is just text and can be edited with any editor although you should still be able to download and install the FreeMarker editor plugin from the JBoss software site (as you can with any Eclipse IDE).
There is a lack of good Surf development documentation and this is probably more of a problem than an absence of tooling because once you get the hang of it, Surf development is really quite straightforward and can be accomplished with basic text editors.
If you have specific issues with Surf then please post them on the forum and we'll do our best to answer them,
Regards,
Dave