Yeah the reason why Tony Blair decided to introduce directly elected mayors with executive powers was that he intended that only his stooges would get to stand as Labour candidates. Sod leaving it to dodgy elected Labour Party members in committees to incorrectly decide who the leader should be.
Then a ‘US tabloid style’ campaign backed by his mates in the media such as Rupert Murdoch would ensure that no politics would be discussed, instead, utterly irrelevant issues would be the deciding factor, resulting in the correct stooge being elected on election day and Tony Blair maintaining his complete and total control of all aspects of British political life. It didn’t necessarily go according to plan. Devolution was also viewed in a similar manner.
It never had anything to do with democracy, and everything to do with power and control. A bit like the House of Lords “reforms” really.