My four star players, who were five star last season, are training faster than anyone else in my team. I don't know if it's as fast as last season, but it is faster than the new young 5/6* players I've got this year

That being said, I replaced almost all of my four star players with 5* who were close to 6* - no matter how quickly they train, it will take a long time to get them up to that standard