Mystic Remora has a much lower mana cost and is much harder for your opponents to play around, but it has that pesky cumulative upkeep cost
You can frequently get two ETB triggers from cards like Spine of Ish Sah, or sacrifice your Executioner's Capsule-Warform token once youre done attacking with it
Whats the Difference Between Draft and Sealed
Llanowar Tribe
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
There are also a lot of triggers, from lands entering, face-down creatures entering, and from drawing cards