Note I can see one problem already. because map modding in EU3 is much less a chore than in EU2, and province IDs are "flexible," any converter you make for EU3 to VR will have to note that it can only be used on base EU3 games that do not have any extra provinces added. Otherwise the province converter will not work for additional provinces added - and since all land provinces come first in EU3, any provinces added by EU3 players on their own would likely convert to ocean provinces with your converter.
I think this is a great project being developed, but you'll need to make very clear that it will not work with EU3 maps modded by players, or with mods like MEIOU, unless specific province converters for those mods are developed.