It's even more obscene when used with a multiclass Barbarian, whose Pressing Strike at-will can be used with a two-handed weapon, and who gets many powers that automatically push and prone every round.
Invigorating--If you are trained in Endurance, you gain your Con mod in temporary HP when you hit with an Invigorating power. If you have the Battlerager Vigor class feature, these temp HP stack with other temp HP, and if you are wearing chainmail or lighter, you gain a damage bonus as long as you have temp HP. Yes, there is an Invigorating At-Will, which is just a generic attack with Invigorating.
Question:
Ok, Invigorating stacks with other stuff, but does it stack with itself?
He also gets a stance that knocks anything he hits prone. Basically it means the enemies are going to kill another PC instead of bounce off of the barbarian's temporary hit points, because they can't get near the barbarian.
Grr. Even worse, draconic arrogance stacks entirely too well with Trample the Fallen, giving that build 1[W]+2[STR]+CON tide of iron at level 16. Since your dragonborn fighter is gonna want a high con for the breath anyway, and that build wants wis and dex a little less...
Ouch.