One level below Hobbs and Hutton are likes of Sehwag, Border, Miandad, Nourse etc. Another level below are Trumper and Morris. Trumper was not even a regular opener, as a matter of fact. I know he is quite romanticized but I am not fully convinced of his greatness. May be I don't know enough so I will be happy to be told something I don't know. I have heard arguments like he played with aggression and little regard to batting average, but if that is not a legitimate defence for Sehwag, neither should it be for Trumper.
Of those you named, only Sehwag is an opener and if you think Morris and Trumper are below them then try Hayden and Simpson - both who averaged 50+ as openers.
Trumper is held in high esteem for the way he played rather than his pure numbers - which are actually very good once you account for his era. Generally, I don't pick players from that era. But again, even in terms of averages the difference between Hobbs and Hutton and Morris+Hayden still cannot account for the huge gap Bradman (and Gilchrist) provide with their superiority.
There have been a number of threads about Bradman which I generally did not post in because I knew I will get exact same reaction, in spite of the fact that I have argued ferociously against anyone trying to suggest Tendulkar > Bradman. My opinion on Bradman has slightly changed having grasped the extent of his struggle on wet wickets. 20-25% better is of course speculative and therefore I avoid stating such numbers, may be 30-35% better is more closer to reality which basically means that Bradman would average 75-80 in a full career in a different era (any era post 1950). And that should not be an outrageous assumption considering that he averaged 88 against England and West Indies combined. Still he is comfortably one or more levels above any other batsman, however his position as the greatest cricketer is more seriously threatened by Sobers and Imran than I earlier imagined. Also don't think he is worth 2 ATG batsmen.
Re his contemporaries, I do think that Hammond and Suttcliffe faced superior bowling in tests than did Bradman. Verity and Larwood were good, but not top drawer like O'Reilly and Grimmet. Hobbs and Hutton hardly played in the same era as Bradman. Hobbs averaged ~57 (?) before WWI while the second best test average was ~48 (?), which puts him quite comfortably in the highest class.
The idea that you could simply slash 20-30 points off one's batting average and not account for batsmen playing in his era or directly before or after his is incredulous. The idea that the difference between the bowling attacks - even if we take as a given that Australia's bowling attack is/was much better than England's - is
so much that it drops Bradman's average some 20-30 points but hardly touches Hobbs', Hammond's and Hutton's, for example, is bereft of much logic. Especially when you consider that before Grimmett and O'Reilly became a tandem - that only lasted 3 series IIRC, one which they lost - he was already averaging 103 against them...when England's attack was stronger than Australia's.
If one attack was 4 Glenn McGrath's and the other 4 Brett Lee's it still wouldn't come close to explaining the difference. Nevermind that England's bowing attack was good enough to beat Australia twice in an Ashes and draw them once, because you make them sound like they were Bangladesh. That must mean the likes of Harvey et al would have averaged 10 if they faced decent bowlers, eh?
And yes, I can't help it if only saying that Aus will crush Eng and WI will satisfy you. I certainly think the these 3 are very close and I will give a slight edge to Aus
It's hard to say they will crush the others because even Bradman is human and could score 0 and effectively wipe out the advantage he brings. So to assume that every test would be a forgone conclusion is dishonest. Then again, to assume Bradman would score 0 too many times and the other batsmen who aren't near his level will succeed is stretching the bounds of credulity. I'd simply say that Australia's team is so good, has all the bases covered, that it's not a matter of who is 1st because that is already taken care of. It is who is second amongst, IMO, SA, WI and ENG.