Adding the Griquas and Pumas to make a pro16 would make a decent competition.
There could be 4 conferences of 4, SA, Ire, Wales and Scot/Italy.
Play home and away in conference, keeping local derbies, (6 matches)
Play every other team just once home or away, (12 matches)
This would still mean a two week tour in SA for teams, so keeps costs the same there, keeps the local derbies, but most importantly it reduces the number of games by 3 weeks, meaning less overlap with the international matches.
It also means that player welfare will be easier, and teams will have their internationals for more matches.
The play off would be the top team from each conference to keep the interest across all regions, and the next 2 best records; top 2 conference winners would get byes in week one of the play offs.