Its often better to have a lot of low-cost cards than a lot of more mana-intensive ones
Since it's a mana cheap instant, you can do this in response to targeted or sweeping removal to get cards, as a sacrifice or it can send something to your graveyard about to get exiled by Swords to Plowshares, or to get value out of a chump blocker about to die anyway
With Abyss Proxy Shop, you can play with Bitterblossom and every legendary Commander staple you need all without spending a fortune
Further Upgrades The first cards I'd pick up to further juice up the deck would be untapped mana-fixing lands: Watery Grave, Shipwreck Marsh, Underground River, Morphic Pool, Darkslick Shores, Polluted Delta, Sunken Ruins, Undercity Sewers, Urborg, Tomb of Yawgmoth and then maybe a couple more Island / Swamp fetches