Still think that a four year cycle of
RWC, Lions, Regional Champs, World League
is the ideal situation.
Move the July tests to September, move the November tests to October and run as one complete block of 7 weeks.
Regional champs, (using Euro/Africa as example)
10 teams in 2 groups of 5 play home or away, with top 2 in each group playing in semi finals and also qualifying for World League.
Teams would be 6N plus South Africa, and next highest ranked 3 teams from Euro/Africa.
Group A: Ireland, SA, Scotland, Italy, Romania
Group B: Wales, England, France, Georgia, Spain
This would be maximum of 6 matches over 7 weeks. T2 teams get opportunity to play T1.
Similar for Asia/Pacific and Americas.
World League has divisions of 6 teams, (2 from each), again giving T2 teams opportunity to play T1.
This would be home or away series, (careful planning with travel needed), giving 5 matches in 7 weeks, like the current 6N.
Using current WR,
Div 1: Ireland, Wales, NZ, Australia, Argentina, USA, meaning the Bledisloe would have 3rd match.
Div 2: England, SA, Fiji, Japan, Uruguay, Canada
On the idea of 6N and RC, I would move the 6N to August and add in Japan and USA team to the RC. Play them both at the same time with 5 matches over 7 weeks.
Then add a PI team to Super Rugby.