damien: it was really awesome to win this, very thankful to TrollumThinks!
I have checked if it is possible to upgrade to Royal Edition later if the necessity arises. But it isn't! Probably the worst marketing decision ever...
TrollumThinks: We've asked Obsidian about it - they say it's in Paradox's hands (them being the defacto publishers on this one).
Seems odd as it's basically "Here, take more money" , "No, thanks"
Is there a wishlist item on gog about it?
Edit: Yes, there's a wishlist item:
https://www.gog.com/wishlist/games/pillars_of_eternity_upgrade_to_champion_royal_editions please vote