You do not need to download patches prior to Patch 1.03. Downloading Patch 1.03 contains all previous patches. Downloading Patch 1.03 will provide you with all patch data available.
Various changes have been made to code and resources to support the Dragon Age: Origins - Awakening expansion pack. Most of these changes do not affect Origins itself.
Some players were experiencing increasingly long load times. A major cause of this problem has been fixed.
At higher levels, non-player characters now receive a bonus to armor penetration. This mitigates an unintentional imbalance with well-armored high-level characters, since armor penetration previously did not scale as aggressively as armor itself did.
Elite-rank enemies (lieutenants) can no longer be shattered. This preserves the intended tactical design of many combat encounters.
Portraits for summoned creatures (like a ranger's wolf) were displaying improperly while in the party camp. This no longer occurs.