In regard to foreign nationals travelling to and from Poland, obviously Gdansk was an option, but also Berlin and Prague. Now BFS has non of these destinations. Certainly with the abandonment of GDN, Berlin could be again sustainable, with access to not only the German capital, surrounding area, but also north and north-western Poland.
Berlin seemed to operate fairly sustainably for a number of years before being pulled, potentially due at that time to the introduction of Gdansk.