I was always known for my outspoken criticism of managers and in fact my No2 son who is at Swanwick often tells me that these days I would be sacked for some of my previous form, however I have never entirely agreed with the view that ATCOs who get promoted were useless operationally.
At Heathrow I can recall several first class controllers who became 'seduced' by the idea of promotion, Paul Louden being the prime example, but Paul Wilson, Brandon Chapman etc were no slouches either. I know one or two decided to try their luck because they did not fancy the thought of being either Tower only at LL or Approach only at LATCC. It has always been my view that the splitting of Tower and Approach at the LTMA airfields and possibly even TMA and En-Route was the most crass and costly decision ever made by management.
Of course there were examples that were useless and became managers, 'no names and no pack drill' as the old saying goes!