According to a translation by Pawel95 on Reddit, an interview by Gamestar of the PR Manager and a quest designer at CD Projekt Red revealed that the new region’s map size in The Witcher 3’s new expansion Blood & Wine seeks to match all the islands on Skellige combined.
While size alone does not necessarily mean an abundance of content; it was revealed that, according to the quest designer, sometimes the team felt like they ran out of space to put content in Witcher 3. So it seems a safe bet that people will be satisfied to find a new land chock filled with content. This is especially as the team believes strongly in a fair “price/content” ratio, with consideration to how much people got for the $60/£40 base game.
In addition, it has been confirmed that the graphics for the new area is an improvement in comparison to the original game. While details of what kind of technical advancements CD Projekt Red have made are unknown, an example they gave was considering if they were to transfer the improvements to the grass to the whole land from the base game, rather than just the new DLC region.
There was also information beyond Blood & Wine. It was disclosed that CD Projekt Red may possibly discuss the idea of releasing a Game of the Year edition of The Witcher 3 (i.e. with all patches, DLC and expansions included), although besides the potential of discussion nothing was confirmed. In addition, it seems that previous titles in the series wouldn’t be seeing any attention as they do not plan to remaster The Witcher 1 or 2, nor release a retail edition with the trilogy in one package.
Blood & Wine looks to be the second of the two confirmed major expansions for The Witcher 3, looking to be larger than the former expansion Hearts of Stone (which was set in the already existing land of Velen, one that was expanded in size with the DLC). Upon release it will be $19.99, although you can buy it now in an expansion pass for $24.99 (which includes both Blood & Wine and Hearts of Stone). The release “should be before E3” (i.e. 14th of June), although no specific release date has been announced by CD Projekt Red at this time.