I think you'll find with HD coming in a lot of things may change (perhaps even for the better).
Everyone will have HD tv because it'll be the only tv there is (once they switch it over completely) at which point every existing tv channel gets 2 extra channels.
One of the craziest side-effects for League fans is that this means any games not considered 'good enough' to draw high enough ratings will just be shunted to one of the other channels.
Think Melbourne. Think extra channel. Think League for Melburnians at a decent hour.
Actually that goes for anything. There will be absolutely no excuse for any channel not to air any of their sporting coverage live for programming reasons. There will be no excuses except the cold hard truth- we dont want to show it till it rates better. Could still be a problem for international and other nation-stopping events if channels want to eek out every last rating drop by delaying it to prime time but for your humble Mexican League fan the way should be clear to watch the footy fairly close to kick off time.
Channels will be desperate for more content as well because now they need 3 times as much. That's why Ten is going all out for American sport stuff- they're devoting one of their new channels just to sport and the only stuff people havent already taken is the American stuff. They've also got the IPL and I'm pretty sure some of the soccer as well. With AFL there will also be wall to wall ping pong but with their split with 7 this may get messy. Over saturation may ensue but I'm not sure if that's good or bad for League.
Expect plenty of replays for stuff that is supposed to be important and endless cheap spin off shows like random footy content shows to fill the air time. If they were struggling to fill late night time slots before they'll be really struggling to fill 3 channels of late night stuff.
Which brings us to the Super League on 9. 9 have League and they're looking for more content that will still be recognisably 9. The Super League fulfills that criteria by building on the NRL coverage without requiring any new outlay for commentators etc.
They'll be happy to play it live because they'll also be happy to repeat it again the next day and, perhaps even some other time during the week, just to fill air time (remember- they have to fill the extra air time without any increase in advertising revenue. Repeats dont cost any extra so they'll be using them a fair bit).
Throw in TiVo and you could just cue up a whole 24 hour day of non-stop League action from the week, organise to have your weekend start on a Monday and watch it all back to back with the push of a few buttons, avoiding any and all other tv programming as you go.
What all this will do to ratings is anyones guess and the long term future for tv is hazy at best but it should be interesting.