It has one outstanding common removal spell, two strong common removal spells, and three strong common creatures
Best 5 Color Mana Ramp Cards (Esika, God of the Tree, Fallaji Wayfarer, Jegantha, the Wellspring) Good 5 color mana ramp options are tricky because they tend to cost at least 5 mana to include all 5 of Magics colors
Build tip: Lean into looting effects, ETB creatures, and graveyard synergy
A two-mana 3/3 Flying Vigilance is a great deal here, even if you cant play it until later
At first blush, at least, Prototype has the hallmark of a solid keyword in that its reasonably simple to understand at a glance while simultaneously expanding the branches of your in-game decision tree in interesting ways
Combine this with the fact that Quill is an item, and thus harder to interact with than other card types, and you have a recipe for rapid Ink development