Those are good areas. Environmental issues interest a lot of Canadians, but the point to take home about the experience in other jurisdictions is that nobody is smart enough to actually know in advance which data sets are going to be the most valuable. However, that's a feature, not a bug. The beauty of making data more available and providing people with the permission, the encouragement, to go ahead and add value to it is that it doesn't cost the public anything at all. It's basically people taking it upon themselves, whether for commercial benefit or in the public interest. People will make use of data that you never thought they would make use of. They will find ways to combine and reuse data in ways that we never envisioned.
The value comes in making it available, but nobody could ever know in advance precisely what's going to be valuable.