I'm not advocating we change again but I dont like the current system and I don't agree that a straight league would be a disaster.
The first two or three years of Super League were first past the post and then a Premiership type play off.
Obviously fans like the drama of a play off and Sky have a hyped it up but it isn't a measure of the best team in the competition. The LLS is by far the most difficult trophy to win and deserves greater recognition.
On a first past the post system Huddersfield, Warrington and Castleford would have been Champions over the last few years and that would have been a fairer reflection of the League.
I would also suggest that there are dead rubbers in the current system. A team only needs to win say 66% of their fixtures to get in the top 5 so their other games are of no consequence.
I do agree with your idea about increasing the League but I think the Grand Final system is a bit like the old story of "The King's new Clothes" we all know that the League Leaders should be the Champions but no one wants to speak up.