They brought back the older characters because of the stories that were being told or because editorial doesn't have the balls to maintain their ideas. There are still people who argue that Sam never should have stopped being Captain America and that preferred Jane as Thor. Kamala Khan is selling better than Carol's book (which is selling more than both Captain America and Iron Man with their classic roles). The point was that when Marvel did this, people liked it for the most part. I haven't really seen anyone all that happy about them doing it with 5G.