What game does Australia have the players for? Rennie was too complicated, Jones was too much of a change, Schmidt is too Ireland....what is the game plan that suits the Australian player?
I don't think any of these things are quite true, or at least they're much more nuanced than that.
Rennie wasn't too complicated on the face of it but he struggled with the step up to representative rugby (as opposed to club) and the way selection and development changes. His biggest issue towards the end is one a lot of first time international coaches are guilty of making after a few years - gambling too much on selection, hoping either the aging star or the hot new thing was going to be the answer to problems he had let fester in key positions. It's not club rugby though and you can't sign your way out of problems - Cheika had this exact same issue later in his tenure. He also probably struggled to maintain an effective coaching unit, but that came after the other issues and might have been a consequence of them. Certainly doesn't help coming in without support staff you've already worked with though.
Eddie wasn't too much change, though it was a lot in a short period and probably could've been more successful if it was staged. His biggest issue was a terrible coaching team, made up of coaches who either weren't up to it or were being made to coach a discipline entirely different from their skill set. They had no hope of ever being able to effectively communicate his plan in such a short time frame, or respond on the fly as the situation evolved.
Jury is well and truly still out on Schmidt and I think it will take time to bring the players up to speed with his style, as it did with Ireland. He's definitely not helped by the fact that 3 coaches in 3 years and a team going bust has impacted development and planning, and has accelerated the departure of players at all level of the game, but thankfully that seems to have settled now. There are clear signs the team is building and he seems to have a good coaching unit with some he has worked with before, though it may still need some changes. I think there's a fair bit still to play out on exactly what Schmidt 2.0 looks like, and I very much doubt he is aiming for a carbon copy of his Irish style, but the foundations will be similar and that's what he's been trying to build so far.
I expect we won't really see the shape of it until the Lions tour next year, where he may well have a few things he's kept up his sleeve to spring on them, but that requires he gets those foundations as solid as possible. The biggest plus he has with the Wallabies going into that series is the unknown they represent with such a short lead in and so much change in the past. That's also a huge part of the challenge facing him, but the only option to seems to be to use that to his advantage as much as possible.