One of the things he touches on but doesn't go too deep into was the value of the NRC for this - if each of the 5 super teams are drawing from 1-2 base NRC teams, rather then straight from their 8-10 clubs, then you can maximize the cohesion in the super teams. That helps the cohesion at the top level. More management of contracting at an RA level with an eye to cohesion can help this as well.
The other option that maintains the 5 teams is a layer between super and wallabies - state of the union, Pasifika vs All Stars, etc. As a one off, this probably doesn't do much for cohesion, but a 3 game series might help. That depends on the effect it has on wallabies tests/camps though.
Putting it all together into a "5 tier" model (club -> NRC -> Super -> 2 team Domestic rep -> Wallabies) could be a way to ensure talent is condensed to bridge the big step ups (NRC in between club and super, Rep in between super and tests). For example the reds pathway would look like Hosptials cup-> NRC -> Super = 9 teams -> 2 teams -> 1 team, and then that would join in nationally with Super-> rep -> Wallabies = 5 -> 2 -> 1. Getting the scheduling right on this might be tricky, and it requires that rep level to be generating cash flow pretty quickly, but both state of the union and Pasifika vs All Stars should be capable of that. My preference there is probably for Pasifika, as it offers us a point of difference from league and could really help with Australian rugby's popularity in pacific communities like Western Sydney and Logan.
Failing any of those bigger, more ambitious options? Bringing back Australia A is probably the easiest way to add cohesion and bridge the gap between super and test match rugby.