I agree with @sacredlilac on the need for the use case. I keep trying to find a solution for the same problem where I am on my iOS device and want to clip the article and add new tags to it.
@PinkElephant - You describe a technical limitation of the current Evernote web clipping design. But there are other apps where someone can create tags on the fly. For instance, Pocket's clipper supports adding/creating new tags while clipping. They have a Siri Shortcut support for their create note step where you can say for tags: 'ask each time'.
Bottom line for me is that I use Evernote less and some other apps more to collect information while I'm researching/browsing.