If the 2 top leagues were to amalgamate, and a limit of 2 GP riders imposed on each team, it would make it far easier to have promotion/relegation, without teams who go up or down having to change their squads wholesale. That in turn makes speedway a much more viable product to the likes of Sky.
It would imho be better to improve the standard of the current PL, rather than just drag down the standard of the EL. If both divisions could have access to the Sky tv money, it may allow an equivalency of pay scales across the two main divisions. If the lesser teams could then afford a Peter Karlsson or Lukas Dryml the standard goes up. Riders are less concerned about dropping a division, more stability ensues.
Just some thoughts...
I imagine one or two EL promoters won't want to contemplate such large changes though.