Steve Bull? Yes he was. Made the Italia 90 squad; although never really a key player. Gary Pallister was in Division 2 when he won his first cap as well.
If the England 23 were to train together 4-5 times a week for 10 months a year and play 40-50 games a season then they'd be a very good club side - top 4 certainly. Any half decent club side would do ok in the World Cup because of that reason.
The notion that you could put a squad of 23...