I don't think it's weak when compared to Instant Revival
Instant Revival: 2SP, Any unit LV4 or below
Aura: 4SP, Only Refess, revives any level, and can bring two more copies back from the cemetery if the opponent has a LV4 or higher on the field.
Though of course the downside is that it can bring copies of other units if it shares the same level and level changing units like Phoenix Chick can't get the cemetery effect. Sometimes the opponent is only playing LV3s and if you don't carry Miracle Fruit for LV manipulation or if the opponent has level manipulation like Mermaid Spear Fighter then the cemetery effect will be negated.
Even though people prefer to use it in bigs because they have less options for revival, I have used it on Fistara because the file didn't use any other LV3's. When playing Gowen versus someone who uses True Emperor, it really hurts when that Aura gets played after using all your Sakuras.