I like that idea, like a 'finals period'. It is probably less fair as any team going through a strong patch at the end of the season could win the whole league, but I think it would generate excitement and would be the only thing likely to allow a team outside the OF from winning the league.
I quite like what they do in the AFL at the end of the season. Top eight teams all go to finals, top four have a 'double chance' to reward them for being good during the season and the top two get guaranteed home games. Attendance at the Grand Final in the AFL is year on year one of the highest sporting attendances in the world. Whilst the SPL wouldn't generate that much excitement I think it would help, and crowds for the last few games would probably be good and it would be exciting to support a team trying to get into the top four play-offs, instead of just Europa League qualification. Unlikely to ever happen but personally I like the idea.