The bridge is currently unsafe for pedestrians for the reasons listed.
The work needs to be carried out urgently.
If the result is a handrail on one side of each stair case, the other side effectively being a cycle lane, then that is fine by me.

However, I think this bridge is an unreasonable obstacle for most cyclists, and very few use it. This rail/channel is not going to change that.

Also I think it questionable whether the rail is safer than the planks:
A dropped bike will be more of a hazard on the rail IMO.
Will the rail provide any grip for a (dismounted) bike in the wet? It looks very slippery.
Will kids be drawn to the rail to see who can skateboard/ride down it?

Has anyone come across these cycle channels before?
I am far from convinced.