One of the problems with the warrior class is that in a high-rage situation, warriors have to spam Heroic Strike in addition to their normal abilities. A lot of warriors complain that this makes their gameplay physically stressful, and Blizzard has been looking to alleviate this issue.
However, Heroic Strike is the level 1 ability, the first ability given to new warriors. Any change to it would greatly change the initial levelling experience of warriors.
I think Blizzard should swap Heroic Strike and Slam. A warrior would get Slam at level 1. Then Heroic Strike would be an ability gained at 30 or so, and could be changed into a better form of rage dump.
The other advantage would be that lowbie warriors would have a bit more rage, as they wouldn't lose the rage from the Heroic Strike auto-attack. That means they could press more buttons, and it would make low level fights a bit more fun. I have a lowbie warrior, and Heroic Striking is a little boring. You really live for new abilities, or for Overpower to light up so you don't have to just wait for Heroic Strike.
Plus, with the changes to defensive stance, and since you have Sunder and Revenge, I don't think you'll really miss the threat from Heroic Strike for low level tanking.
As a mid-to-late-game ability, Heroic Strike could be tailored as an ability specifically used in high-rage situations. For example, what if Heroic Strike cost 60-75 rage, but did a correspondingly large amount of damage and threat? Such an ability would be useless at level 1, as it would take forever to build that much rage, but it might be a very valuable late-game ability.