Could we not only modify recipes but also add new ones?
For example, as an extreme case, we could keep the recipe that processes one iron ore into one iron plate as-is, while adding a recipe that processes one iron ore into one copper plate. In that case, it would be good if we could also set the machinery required for processing.

I do plan on supporting recipe additions eventually, as for recipe category changing I'm waiting for 2.1 to come out and merge category and additional_categories into one field. This mod is extremely taxing to work on, so I'd rather not have to do anything twice.