Being libertarian-oriented, I would probably favor an application of
strict scrutiny far beyond what the courts currently use. However,
intermediate scrutiny is used in many areas of law besides just gun issues. For example, many laws dealing with gender discrimination and sexual orientation receive intermediate scrutiny.
Likewise, content-neutral laws (the law applies equally to all speech regardless of the content of the speech) affecting free-speech receive intermediate scrutiny (which has led to things like "free-speech zones").
The problem with "intermediate scrutiny" (also called "heightened scrutiny" by the Second Circuit) is that it isn't well defined and as a result courts can (and do) apply a standard that is really little more than
rational basis test to cases that should be holding the government to a higher standard.
In this particular case, that is exactly what happened. The only parts of the law the Second Circuit didn't strike down were those that the government literally made no effort at all to defend. This was a complex law affecting two different states and composed of hundreds of smaller provisions. It removed rights that had existed in these states since the founding of this country and directly touched on the Bill of Rights and the Second Circuit's version of heightened scrutiny upheld every single restriction the government submitted evidence on.
And then they went further and included in their decision things like "We'll assume these firearms are protected by the Second Amendment even though for these reasons that might not be the case..." which was basically a "How to"guide for gun control groups to argue the issue of common use against semi-autos. And even the two parts they overturned, they practically invited the government to submit evidence on that and try again.
I found it to be a grossly partisan decision.