ABDV didn't always bat at 5. He did open for a substantial portion of his career. He was terrifyingly good all career and other than Lara in tests, I've never been more frightened to see a batsman come to the crease. Even when Australia were the clearly dominant side, it always felt like ABDV could put us to the sword.
The feeling is different with Kohli. It feels like he can be worked around. Yes, he can put up the big scores, but he doesn't usually totally take the game away from your side. He's obviously better at chasing than setting targets, which is his strength, but I feel like he's really just a newer, fresher Dhoni in that regard.
The player ODI Kohli most reminds me of is test Ponting. Ponting in tests between 2002 and 2007 was on a different plane. He would go out there and punish the bowling for taking the openers wicket. He simply churned out the hundreds during this era. His average got to a fraction below 60. But then he had the inevitable long slow decline (from about age 33) and averaged 40 for the last four or five years of his career, declining him to his final average of around 52. At the time of Ponting's purple patch, people were saying that he was easily going to break all of Sachin's run scoring records. But it's very difficult to sustain that level of brilliance for more than half a dozen years at a time.
My point is that Kohli is in a ridiculous purple patch right now, possibly one that is greater than anyone else's before him (though Amla's was pretty damn memorable at the time). But that's not necessarily a reason to rate him as a better player than Viv or Bevan or ABDV or Tendulkar quite yet (though personally I do rate him as being better than Tendulkar).
And if you need any evidence that form can turn quickly on players, look at Shaun Marsh. Averaged 60 last calendar year and now isn't even playing for Australia, despite Australia missing their two best batsmen.
