There are plans and visualisations, but I'm not sure if they have been made public yet. From what I have seen the Barrier Ditch is likely to become publicly accessible. The rampart and guardhouse will be restored between Dock Road/Church Hill and the river, but the ditch will not be fully excavated. Instead the course of the ditch will be marked out in paving and the original line of the footbridge will be indicated. The line of the riverfront has changed by several meters since the ditch was filled in, so there will be an area of grass between the end of the indicated ditch and the river.
A 'fort' themed adventure playground will also be included, and it may be that part of the ditch is exposed to full depth, but with a glass floor over it at the reinstated ground level.