I know the DL card is meant to hard counter another card, but it is extremely UP imo. It usually doesn't heal that much more than Heal or SoD, but it kills every creature. Sure, it hardcounters that other card, but it is basically only worth using if you have no other creatures, since letting those creatures attack is usually better than sacrificing.
Better mechanic to counter a creature on your field would be something that sacrifices one creature or something.
Suggestion to keep same mechanics, but make it stronger: Divine Altar (Permanent) Ability: Divine Offering: Sacrifice target creature and heal yourself equal to its HP and deal damage to opponent equal to its Atk.