The RBR young driver program is to find the next Vettel, not really to hone and develop the skills of young drivers. If Vergne or Ricciardo really show that sort of potential then they should expect to get promoted, but I think Red Bull would be better off going after Hulkenburg or Massa if the two STR drivers do not jump off the paper after 2 seasons.
I think Chilton might be flattering Bianchi a little, but I definitely expect Bianchi to be around a long time. But to promote him to an RBR seat after 1 season at Marussia would be incredibly risky and not a good idea, unless he really shows something other than the ability to outpace Max Chilton and Caterhams. Remember, Findia chose the more expensive Sutil over Bianchi after seeing both of them in the car in Winter Testing.