I honestly don't see the advantages of staying in Segunda A. We can't sign players for the B-team in the summer and the best B-players are leaving the team. The current Juvsnil A cannot fill those holes that are left behind, so next year's gonna be even more problematic.
Tougher competition is better for development IMO. Also talented young players like Suarez or Halilovic won't come to play in 3rd division.