Graf said:
If you're having trouble figuring out why then run two otherwise identical dwarf and (your version of an) Orc against each other.
Your Orc will win 80+% of the time. If your confused about why just read the economy of actions article on wotc's home page and remember that you've effectively given your Orc 25% more hit points.
The orc wins the melee fight where nobody moves and the average incoming damage-per-round is low enough (in this case, because it's a one-on-one fight between heavily armored combatants) that using a Second Wind is actually a good idea.
The dwarf still does better in bigger combats if he wants to double-move in the same round as he heals, or use ranged attacks, or use a power that's better than a basic attack (say, Cleave).
I am far less concerned with whether a single orc fighter PC wins against a single dwarf fighter PC than I am with how well these PCs compare with each other when both are fighting monsters. It may be that the Orc's +2 speed when charging is enough of a secondary bonus that the "Second Wind" usage is fine, but it's far from clear to me.
To see some of where I'm going with this, try running
two dwarves against
two orcs, and (provided the combatants are close enough to use Cleave and Passing Attack), the dwarves will have a much better time of it they will be able to use Tide of Iron to line up Cleave attacks for one another, and Stand Your Ground will prevent the orcs from doing the same back to them. The dwarves may still lose more than 50% of the time, but it will be a lot closer. Also, during the times when the orcs win, it will be costlier for them in terms of daily resources (they'll use two healing surges each compared to the dwarves' one each).
