I would agree 100% with Steward. I just don't think Haye is smart enough to benefit from Steward's coaching.
I don't know what Adam Booth's work was behind training and promoting David Haye but I surely can't see Freddie taking pearls out of empty shells. David Haye only commited himself to fight in the 12th round, actually he started to get out of his defensive shell when he was wrongly ruled a knockdown in the 11th and he clearly realized he could not be in front of the scorecards. B'sides, that big overhand right in the 12th and the straight right that connected after 4 rounds was precious too little to claim anything. Freddie Roach basically has been very sucessful with Manny Pacquiao reworking his boxing abilities alongside with that lion-hearted willpower of the Filipino. I don't even believe he can boost up a technician with fire and energy in Khan against the top dogs so the answer is no, sir.
It won't make a difference to him beating the Klitschkos. There are physical advantages that no amount of input or tactics from a trainer will change.
If Haye was more aggressive, he would have been knocked Haye. Haye did all that he was able to do, without being knocked out. Booth himself said that the right hand Klitschko landed in the 5th round just completely scared Haye from being aggressive.