New content - good.
New map - questionable.

New map means spending resources that cannot be used on improving the Exiled Lands instead.

The EL map seems to have more than enough room to add several dungeons, areas and so on, as modders have demonstrated. What’s better: A new map with four new dungeons or eight new dungeons for the Exiled Lands? I’d say tha latter will add more content that’ll be relevant to a shrinking player base.