I think the format of the regular SL season is intimately tied up with the formatting of the international game.

SL needs to have a sensible, and fair, number of rounds (for instance, Warrington, Huddersfield & Catalans get an additional 2pt gimme by having their magic weekends against Widnes, Salford & London, as against Leeds, Wigan & Saints, who play Bradford and each other).

Plus, the Challenge Cup needs to involve all teams and be a straight knockout competition. With all of Super League, Championship, Championship 1 & Elite One Championship you have 44 teams. That would leave 20 spots to open qualification from all teams at all levels who wished to enter, with a subsequent pure knockout over 6 rounds to the final at Wembley.

6 CC Weekends, 26 SL weekends leads to a 32 week (call it 8 month) season, starting the last weekend in February and finishing in October. 5 Nations to be played in June/July, and Autumn internationals to be played in November.

Any stats on number of imports? I seem to remember most clubs having 5+ imports in the 90's

I think it was no more than three in the 1990s.

Why would Sean O'Loughlin play for Ireland when he can play for England?

A minor point, but i would like to point out that Eamon O'carrol plays for Widnes.