I think #7 is negotiable, but unless there are really special circumstances (down by one in the series with one Test to play or a guaranteed road, for example), you need six genuine batsmen in a Test cricket team, regardless of how strong your tail is. Sometimes your wicket keeper can qualify as a genuine batsman, and in the subcontinent Dhoni does which is why India can play that balance, but in Australia I really don't think he does.
I used to be a fan of the idea of balancing a side by having several players from 6 down to 9 or so that could contribute, even if they weren't what you'd call frontline batsmen, but I've really gone off it now. Cricket just doesn't really work in a way that two 30 average batsmen collectively would be worth as much as a 45 average batsman and a 15 average batsman; there's massive variance in batting so you need six genuine batsmen who can play a proper batsman's innings in your side. The fifth bowler when compared to the sixth batsmen is really a massive luxury.
When the top order gets blown away, I don't really have any faith in Dhoni, Jadeja, Ashwin and Bhuvi arresting that situation. If the top five lays a platform then they can definitely all chip in to turn a good score into a very good score, but I don't think they're going to do much in a situation where they're really needed to score runs. If the argument is that Rohit isn't good enough then it's time to consider picking a different batsman (oh god it's Raina); not a bowling allrounder.