Stuff like this is purely nostalgic and will not work in modern day speedway. 4 Team tournament alone wouldn't work because where are promoters going to finance rider costs for 3 extra away meetings for top riders going by the old format. It's the same crack as people saying there should be a one-off final etc.
Speedway needs totally re-invented from the top down just like domestic Cricket has with the Hundred.
The only way to do this and keep the top GP riders riding in the UK is to have a separate summer holidays competition, a 'Super League' with maybe a modified format.
Team names do not matter one bit, I was always sceptical but franchises work. And people soon find a team to support.
6 Teams would be based around tracks with large followings/finances and the ability to draw big sponsorship and fans in from other teams, 5 man teams (squads with no guest system) sticking to the usual Monday and Thursday priority race nights from mid July to end of August. 30 riders required with plenty to choose from.
Example (recognisable to other sports fans) team franchises would come from;
Glasgow
Manchester
Sheffield
Midlands/Leicester
London/Oxford
Bournemouth
A normal 14 team league ran at championship standard would be ran alongside this as usual from March to October for your weekly speedway fix. I don't think the standard of rider correlates to the size of the crowd. The rivalries and standard of racing builds this.
How else can domestic speedway survive? It can't keep going the the it is! Unfortunately, I don't think some of the people running the sport would have the foresight to come up with a 5 year plan to incorporate this 'Super League'