Competetive:
I do not want to play a competetive game without ETC or similar restrictions.
As an out-of-the-box game, 8th edition is not balanced. To make it viable as a competetive game, we need restrictions. Easy.
Casual:
For casual tournaments, to give new players a go and just relax a bit more, I don't know the answer. Honestly I think we need to rely on saying "don't be a dick for this one - leave Mr Pegasus at home". Because if we have no restrictions the noobs will get obliterated. If we have some restrictions it's fairer, but it removes the casual, fun aspect of deadly flaming terrain and game-ending spells.

Composition Scores worked too. They were used all over the place in 7th. Why not now? Maybe the problem we have now is the divide in army books has become too great, and so comp bounces are silly, or not enough. Which I can see being true, but I think with moderate caps in place (

) it could still work. The most important thing about this method is it makes a variety of lists viable, not just the streamlined bullshit the kids are plucking from the internet these days

.
The option I think would be best for casual tournies is a "don't be a dick" statement and the main caps for army lists (just in case), but untouched rules. This means the lists shouldn't be silly (TOs should reject optimised filth lists) but the rules will be the full-on 8th edition blast-your-faces-off ruleset. Maybe have a light comp score in there too.
I think that in NZ we're lucky enough to have gamers who respect the "don't be a dick" approach, and I'd like to see that tried out a bit more. I know I love making weird unconventional lists, and it'd be cool to play against some others too.
Cheers,
Joe