context: in the PHB dwarven weapon training basically provides a +2 to damage and axe and hammer proficiencies, but the later are really for clerics or others limited to simple weapons.
Hammer Rhythm.
The most damaging martial weapon in the game before AV was a hammer.
Hammers give bonuses on fighter abilities just as often as axes, and it's generally of the 'damage moar' variety.
Hammers are not just for clerics no more.
Draco: are they really that "sub optimal", at least for fighters? Their boosts to con, wis, race abilities...all seem to compensate.
In terms of damage, yes, absolutely sub-optimal. The racial abilities ARE good, do not mistake me. But strength based classes end fights quicker which is also an effective form of damage-prevention; killing a foe effectively heals you for all the damage it would have done if you hadn't.
Not to mention, the dwarven abilities in those regards are valuable if you're a fighter, but have less upside for a Barbarian or a Warlord.
Not to mention, every class in the game predicates itself on the ability to actually hit something. Dwarves are at a disadvantage, so superior+2 damage for one feat makes them... almost at the level of a Strength-based fighter.
Fact is, without the additional proficiencies from AV, all DWT is is a heroic-level +1 damage that gets obsoleted at paragon. That's not that great at all across 30 levels. With the proficiencies, it's a feat you take and enjoy and saves you a feat for epic level, while not putting you above the curve.
For something to be broken, it must put you -above- the curve, not just a slight bit beneath it, and DWT only puts you slightly beneath the curve.