Psure there will be enemies with subclasses who will use their kits, I seriously doubt Sawyer pass on that.
I agree with you about feats, but PoE has been bombarded as being bland (even on aspects it really isn't) so subclasses are likely a pushback against that.
Oh, yeah, I'm 99% sure they are going to use them, that's not the problem. The problem is that they'll likely exist in a vacuum, only relevant to the UI and quickly forgotten about. They won't be a thing that exists in the world of Eora. This is a very important issue that affects all the arts, how the elements are used and are they arbitrary and random or have a structural/narrative purpose. The irrelevant names of the subclasses/multi-classes are a symptom of something deeper, something PoE1 suffered from as well - the complete disconnect between elements. Much of the world building is simply a list of something someone came up with. The names of the subclasses/multi-classes are also
literally a recited list of words Sawyer came up with or looked up in a dictionary. We have all these names, places and history, but we don't have a created coherent world in which they matter. That's why I gave the spices analogy, we have all these spices in front of us but we don't have actual food.
Not that having some fluff is bad, it can create a sense of mystery, expectation or being part of a bigger world, but PoE goes overboard with it, being comprised of 90% fluff which these names exacerbates and brings yet again to the table. The blandness of PoE that they are trying to push back against won't be fixed by this, it's just going to deepen the issue.