Loren the GM said:
Initially, they appeared to be covered under the standard DMs Guild license. They have more recently added language to their license that only allows maps of existing content when it is combined with other material such as an original adventure, or materials that expand on a published adventure (for instance, there are several guides to the various parts of Dragon Heist that include maps). I'm sure there are licensing reasons for this (which were definitely not defined at the time of Dragon Heist, when much of this art was generated), but my point is rather the DMs Guild is where artists should be able to engage with the adventures. I'd love for WotC to revisit this and allow new maps to be published there - or as others have suggested, for Roll20 to take this on and license new maps (it would seem if Beadle and Grimm can achieve that sort of license, so should Roll20 be able to). I'd personally be willing to pay a premium for new maps on Roll20 - perhaps keep the original adventure as is, and have a $40 new map pack add-on as well (to cover the cost of the licenses maps)?
I feel the same exact way. And that's just for the Adventures. Personally, I have made several of the FR City maps for my own games, and I would love to release them publicly, but that is not allowed, and outside of the select few that Schley has created, there is a huge gap of quality city maps for one of the most popular settings in all of D&D.