People are answering this seriously? ''Let Dawson fill into his body''? He's a 28 year-old, former middleweight who's been a pro for nine years. He does not fight David Haye, ever.
It's not an outlandish proposition. Dawson is 6'2" and a big LHW. And he still hasn't filled into his body yet because as you said, he's still only 28. He's still filling into his body.
It is though. He will almost certainly never move to heavyweight, of that I'm 99.99% certain. Plus, if he ever was, Haye retires by the end of the year, about October, there is 0% chance that Dawson will fight Haye this year, and therefore ever.