I think it's safe to allow it for any property where it makes sense.
I ran into this with Dungeon Keeper 2 - partial subtitle support. Subtitles are there, but some of them are missed and some are overridden. It would be nice to categorize them as such, so that people will know that it will appear ahead of time rather than being surprised in-game.
The only other thing missing is a "required" property. There's the rare game where you're required to use something (e.g. X-Wing Collector's requires joystick when X-Wing for Dos doesn't). However, that's probably a separate issue.