This is a seriously good idea. The twin lanes over the bridges are clearly not needed since either side of the bridges the traffic is squeezed into one lane or less (going up Honor Oak Park is often half a lane each way). The traffic problems on Honor Oak Park are due to parking up the hill and again down by the traffic lights. The two bridges do not ease the problem in any way.

A pick up point would be very civilised instead of the current practice which requires people to park on the pointless double yellow lines (except that, ironically, they provide a pick up point)

The raised 'kerb' is anti-pedestrian in practice, and your point about people with buggies or luggage having to negotiate the narrow space is correct. I cannot understand why station users should have to be so inconvenienced in order to provide a superfluous second traffic lane.

Pedestrianising the space outside the station would be excellent.

I went and had a look at the space after reading the posting by theplanner and the only problem I could see was the siting of the bus stop on the other bridge, which would stop the traffic if it was the only bridge used.

I think there is plenty to commend the idea, and not squeezing pedestrians would seem to be a reasonable starting point. THis might be worth raising with other very local groups like HOPRA or HENBO.