So the scenario will be
1. You import products
2. Switch to product list and select Recently updated search.
3. Select the products and apply the required categories to them like this: https://www.evernote...ud6-yloTMETLiM
Then it already works at the demo: just select a few products at once, and you'll be able to easily add/remove categories in bulk. That functionality was introduced in version 4.9.1. So, if all products are already created in your store, and you've assigned the desired categories to them in bulk manually, then you can simply update quantities without assigning categories.
But if you're asking about category mapping in the Advanced Product Import, then unfortunately I can't say if/when it happens. It all depends on how many of our clients request that functionality.