Huge size, 38 strength and Power Attack as a bonus feat all are pretty nifty, the hound's bite and claws deal respectable damage, DR 10/silver and magic is hard to overcome, Unholy Toughness is nice on something with 18 charisma, and Body Integration allows the hound to recover HP when it kills stuff. Rend and Frightful presence are hardly overpowered, but a slight net positive.
However, the same hound also has several severe flaws. It lacks thumbs, takes massive penalties to all important rolls in daylight, and is naturally mindless. Bodily Integration, while at first glance a reasonable source of in-combat healing, only works on humanoids, who aren't known for having lots of HD. Oh, and this abomination also has 21 undead RHD to deal with.
To emphasize how bad the last bit is: it means the charnel hound has +10 base attack bonus at ECL 21. Even if it managed to wield a weapon somehow, it'd get only two strikes with it per round. Its fortitude save is a measly +7 at a level where save DCs regularly reach in the high twenties.
It should be clear that the charnel hound simply isn't competitive at epic levels, and therefore deserves -0 LA.