Just to be clear, the preservation age is already increasing in a sliding scale up to 60, unless you are old like me. So you wouldn't be able to access until 60 if the laws remain the same. Like everyone else I think it likely the preservation age will rise.
The govt will certainly transform super gradually into a old age pension replacement in the coming decades, and I'm pretty sure that the lump sum option will disappear at some point. There are rumours ("leaked Deloitte report") that mooting changes such as residual super after death not being able to be passed onto heirs, but returned to a big super pot to be used for others. Not sure whether this will ever see the light of day or be passed, but the govt is certainly getting desperate re funding the aged tsunami. The tax advantage I think will gradually be trimmed to ensure everyone saves their OAP equivalent, maybe a bit more, but I suspect tax sheltering huge amounts will become less and less possible.
For what its worth I sacrifice to the caps, but I am 55 already.
For someone your age (this is the advice I've given my nonmustachian son age 19), I would work out what you would need to put in to be assured of a comfy mustachian retirement say 41k a year (since that is what a single is said to need these days). Work out what you would need to put in above the compulsory 9.5%, increasing to 12%, and sacrifice the difference. I can't do the figures for you because it depends when you want to retire. Consider this a comfy mustachian old age retirement annuity. Personally I would not put more than that in.
You could either decide to sacrifice a lot now and hit the target, then direct more to non tax sheltered investment, or sacrifice a bit less and do a bit of both for longer. The argument for sacrificing more now might be that at least you know what the cap is, and you've got your old man money done. But its entirely personal.
All the above advice is just my opinion and nothing is certain..
The most important thing is to keep your ears and eyes open with regard to changes to super. Not just what is in the budget, but the discussions around changes being floated. And adjust your plan if you need to.