I think that the career of Dickenson shows that referees have a limited life span at the top. I remember when Dickenson first emerged in about 1996, he was quite strict and fast on the draw when it came to Yellow cards. In the early 2000's he developed into a very fine referee, still a little quick to go to the pocket for my tastes but generally very consistent. He performed well throughout the mid 2000's but started to lose some form. In the last few years he has had the odd good game, the odd shocker and has generally been pretty average.
He is retiring perhaps a year or so late, but we should remember him for his good perfomances, not his latter days.
This 'arc' is actually quite common with referees, others that I can think of that followed a similar path are Paddy O'Brien and Wayne Erickson. Towards the end of their careers they were a shadow of their former selves.
