Now that you are done with the VSM exercise, its the turn to list out the issues in for of issue tree.
An issue tree is nothing but a graphical representation of problem and its solution, let me give an example

Issue tree

The above issue tree describes the various cells and the key levers identified for improvement.
It also indicates the potential improvement (in days of lead time) at each head.

Once you are done with the issue tree, its the time for "waterfall" graph.
Again the water fall is quite a simple tool for communicating the potential improvements

Waterfall

The above figure is self explanatory i guess, but just to summarize, the waterfall will depict the improvement initiatives / levers with the potential days savings in lead time.

to be continued ....