Think the age thing has been a bit overstated with Southampton to be honest, they've actually got plenty of experience in that squad and the bulk of their regular starters are 25+, they're just not very good.Maybe everyone has had abit of a look at Southampton this year and have now realised you cant fill your squad with 19 year olds and compete in this league!
1 or 2 are fine, but the rule of thumb is that most of the good sides in the PL have majority 24-29 year olds in it!