The focus nowadays seems to be on youth and fitness.
I had my best refereeing days during my mid 40s after 10 - 15 years refereeing, but by that time you're considered too old to be promoted to the 'elite' leagues, despite having the fitness levels required.
Personally I think a ref should have a minimum of 3 years in the league just below the 'elite', then get promoted, irrelevant of age (within reason), proveded they're fit enough. There will still be plenty of years left for that ref to progress. However, I don't know the experiance requirement in Scotland.
Also, several years ago FIFA lowered the FIFA ref retirement age from 50 to 45 so associatons are looking to get refs on to the FIFA panel as young as possible.
I totally agree with Jaggernaut about shirt tugging, holding etc. The thing that really riles me, and it's seen in all major leagues, are players holding their opponetnts away arms length. This never seems to be punished, so every player thinks they can do it, despite it clearly stating the following in the instuctions to referees in the laws book.
Holding an opponent includes the act of preventing him from moving past or around using the hands, the arms or the body.
Referees are reminded to make an early interventionand to deal firmly with holding offences especially inside the penalty area at corner kicks and free kicks.
to deal with these situations
the referee must warn any player holding an opponemt before the ball is in play.
caution the player if the holding continues before the ball is in play
award a direct free kick or penalty kick and caution the player if it happens once the ball is in play/
If a defender starts holding an attacker outside the penalty area and continues holding him inside the penalty area, the referee must award a penalty kick