Hi,
Regarding file associations, I'll see if Matt can do something with the installer. Otherwise I'll have to mess with the Registry, which is something I've been trying to avoid :-).
As to drag and drop, I've just fixed an issue with drag and drop on Windows, so in the next release you'll be able to drag and drop files onto Choose File buttons in param views. You can already do this on the Mac. At some point I do hope to expand the drag and drop capabilities in TG2 further, for example allowing you to drop object files onto the 3D Preview or network view and have an appropriate action take place. It's not particularly high on the priority list right now though.
Regards,
Jo