I prefer G1 to G4 but I wouldn't like them to bring back G1. It would be better if there was more variety and more characters in the current G4 line with better quality control and accessories. The Zelfs toy line have what G4 MLP is seriously lacking.
I disliked the 25th anniversary retro sets that were released and would dislike it if they remade any others. Although - I would make an exception if they were willing to make the celestial ponies which never were made...