As of 2015 season, I would specify off the top of my head some really good Antipodeans in SL as:

Todd Carney
John Zebolon Ta'ia
Albert Kelly
Terence Campese
Kenneth Sio
Adam Cuthbertson
Paul Aiton
Joel Monaghan
Luke Walsh

Of those I would argue that only Todd Carney and Joel Monaghan fit into the "bad boy" category, and only Terence Campese came over in his "career twilight." The others came to Super League mid career as top players from NRL teams (esp. Sio from Parramatta and Walsh from Penrith). Kelly was an NRL star for Gold Coast when not injured, a tendency replicated at Hull KR.

Cuthbertson - not a superstar in the NRL, while he was seen as solid he has surprised a lot of people this year and he wasn't talked up before he came here by rival fans.

Kelley - not really a top player there lets be honest (i know you have a man crush on him )

Aiton- was at Wakey before Leeds, seen as an average NRL player at the time he came over here.This year his only top year and he is now over 30.

Walsh - seen as a steady away player in NRL as far as halves go, don't know in's and out's but obviously Saints paid top dollar.

Sio - Parramatta, been garbage in NRL for a while but they saw fit to release him? hmmmm.Not really anywhere else to go in NRL from there is there.

Ta'ai- Soon as he has a stand out year, back to the NRL.

None of those players above imo can really be seen as stars or even top players at the time of leaving Australia.None of them left with NRL with clubs banging the door down begging them to stay.Mainly squad fillers.So yes, like i say, this level of player will still come and do well in SL, nothing wrong with that mind.It's certainly no dooms day scenario.

Beg to differ on some of those players. The fact that Parramatta as a team were poor has nothing to do with the quality of individuals. For example in 2014 the Parramatta back three were Jarryd Hayne, Semi Radradra and Kenneth Sio. Jarryd Hayne was in that year the Dally M winner (with Johnathan Thurston), and Semi Radradra was Dally M winger. Kenneth Sio scored a bucket load of tries in that year, and was overshadowed only by Radradra in the team scoring. No doubt Parramatta could not compete with Hull KR's offer when carrying the other two's salaries (Hayne only announced his departure in October 2014). I watched Sio in that year and could see that he was class. He has proved it in SL.

Albert Kelly had a great reputation in the NRL as an attacking half back. He was only released by Gold Coast because they were worried about him being injury prone (which he is).

Luke Walsh was a very good scrum half at Penrith. He was released because Penrith could get Peter Wallace from Brisbane (who in turn replaced him with the outstanding Benjamin Hunt), possibly because of salary cap reasons with an expensive roster already in hand.

You ignore the fact that some quality players are let go by NRL clubs not because the players are not very good but because of salary cap reasons, such as the fact that over time NRL clubs have to increase some players' salaries (e.g. because of representative achievements) and then find that they cannot keep all their very top players when competing with big counter offers (Sydney Roosters releasing James Maloney to Cronulla and Roger Tuivasa-Sheck to NZ Warriors are good examples). That is also why some mid career stars get released from the NRL to Super League.

This will undoubtably see more top players going to the NRL. Still it's better than them going to union.

Super League is lucky (and rugby league in general unlucky) that the NRL did not expand the number of clubs by two or three. It would have seen a massive exodus of current Antipodean import stars from Super League back to the NRL by 2018. As it is, should Elliot Whitehead, Joseph Burgess and Benjamin Garcia be successful in the NRL-- and I think that they will -- expect some NRL clubs to start scouting the ranks of Super League for more English and French talent to import. (I certainly hope that some NRL scout finds Lucas Albert before he is much older, so that he can be properly coached into becoming a world class five eighth for France)

If the NRL salary cap was to double from $7M to $14M (the last tv deal was worth $1billion this one is $2billion) how would that compare with the salary caps of rival codes, Aussie rules, super15 rugby, French and English rugby union?

The NRL and ARL are very similar, NRL up 69% to initial 1.8 billion dollars, ARL up 67% to initial 2.5 billion dollars. I seem to remember the ARL about 5 years ago had a massive marketing and advertising campaign which increased attendances and deals massively, our RFL at Red Hall are not on the same page with marketing so I suppose you reap what you sew.