Although creating the base at BCN is not a bad idea, parallel flying to the same destinations has some symptoms of self-cannibalism.
True, during the summer season the routes like CRL to Gerona and CRL to Reus could be almost as attractive as CRL to El Prat, but in winter... I doubt it. Kind of competition FR versus FR. Well, unless some GRO planes are to be redirected to, say, Nantes, St. Etienne, Trieste, Lodz or Lappeenranta. In fact not so many FR airports will be still unconnected to Catalonia.