"I think it is important to recognise we have achieved the high water mark in a local politician with Lesley"
You might be right, but apart from pessimism I see no reason(s) to think that.
My next sentence might sound pejorative but it's more my take on 'reality'.
LH is a highly creative machine politician (see Morningsider's view above).
Again, I'm not writing her off or trying to diminish her - she is perhaps from a fading age. Politics is more complicated and her party is not currently in any sort of ascendency.
She has undoubtedly presided over a most successful period of increased cycle infrastructure and attitude changes. That is not to say it would have happened anyway if someone else had run the key committee over the past few years.
She clearly encouraged/enabled officials to be a bit 'bolder' than previously.
I would say that David Begg did more for Transport than Lesley, but LH has managed to make a significant difference for 'cycling'. She took over from Gordon MacKenzie who achieved a lot under trying circumstances (partly tram related) and wasn't even re-elected because he was a LibDem. What GM achieved could have been the "high water mark", but LH probably accelerated things.
Begg made the bus lanes happen (LH messed with their use times). Off-road routes were the main cycle feature of the Begg era (good thing too, but relatively uncontroversial).
Begg was 'of his time' and clearly more interested in transport than furthering a political career. Unlike Burns, Hinds had aspirations for the 'next level' of politics - expecting to win a seat at Holyrood.
I have no idea if Adam McVey hopes/wants to take over - or if he would be worse/similar/better, clearly there are people who might do the job with less interest/more hostility (to ActiveTravel).
Whatever happens in May and however much 'high quality people' are put off from standing for councils, I think it's pessimistic/unwise/defeatist to think things can't get better than the ending LH era.