I could talk a bunch about ideas on strictness of criteria and such when it comes to identification questions across the network, but I think that's a genuinely different problem than what we're looking at here. So let's take a different angle and divorce us from the general flock that is referred to as "identify-this questions", because we're not talking about the legitimacy of the question category that tends to be marred by memory - we're trying to look at what we want to do with questions we do admit here.
The first approach to defining a need for such a tag is to get back into what tags are for. Tags serve to help both askers direct their questions, but also for answerers to be able to find the questions they're interested in helping out with - what their expertise caters to. It then largely depends on how this site wants to actually curate these. The ultimate goal of the site, after all, is to serve as a viewable resource of information. The solution may not even be to create a general identification tag, but to instead be more granular in the available options for tagging.
There's a great deal of contrast between questions like "What are these devices hanging out my patio door" asking to identify what a mystery device does, versus "Why do these calipers have this design" asking to identify the purpose of a device's design, versus "What is the name of this kind of screw" asking to identify a name for search and retrieval purposes. These can all be called "identification" questions, just with different degrees of what you're identifying. The first two rely on the same general branch of expertise - the knowledge of "what things actually do" that allows people to know what a device is designed to do and thus tell people who don't even know what it is. However, the first and the third can also be grouped under a different branch of expertise - the knowledge of "what things are called", which may be sufficient in some cases but if the name alone doesn't tell an asker enough, it may start requiring more of the former expertise. These are simply two independent kinds of expertise - whether one wishes to value one or the other more is largely irrelevant because at the end of the day they both exist and are both permitted on this site due to the problems they attempt to solve.
The fundamental issue what often gets brought up in this kind of tagging is the idea of "meta tags", but the actual problem of a meta tag is functionally "This tag, if it were the only tag on the question, does not tell me the kind of expertise I need to use to answer it." We've defined that we can group these kinds of questions under two different umbrellas of knowledge, to which "identification" alone is too vague. Rather, it would be more useful for answerers to know which kind of identification knowledge they will need to use - do they need to know functionality of the item, or do they need to know the name of the item? By dividing the tags into this narrower space, it allows you to more easily direct questions to the right answerers. Folks who can look at a device and can determine the name either by their memory or their search capability can handle the situations where a name is desired, while folks who are knowledgeable about what tools are used for can dispense their information to whose who wish for more than just a name.