Overall this is a step in the right direction.
But it felt like a bug the first time I noticed the change. Also, at the moment it seems like there is no way to close an issue with another status than resolved. And issues that were marked as duplicate by a contributor with a comment ' Duplicate of #x' still show as resolved.
They should probably consider adding texture to closed issues too to add another dimension of possibilities to closed issues.
For example, if you see something with a striped pattern whether it's red, purple, grey, etc.., you can assume it's closed. It would help color blind github users.