Well, the problem here is that the law does appear to call for an environmental analysis of the impact of the rule change. While I think a great argument can be made that there is no impact, the previous administration did not do that analysis (and if they had, the rule change would not have happened before the change of administration).
As a result, you can make the argument that the environmental analysis needs to be made - and now it will be made by this administration if the appeal is unsuccessful. While that doesn't give me a warm, fuzzy feeling the ridiculousness of asserting that concealed carry has an environmental impact should give a very clear indication of what type of firearms policies the administration will pursue when they have carte blanche.
For what it is worth, this judge has popped up before on firearms-related issues such as
McCain-Feingold regulation of the Internet.