The more I experiment with it, the more I think you're right in pulling out the Silverheart. Getting an extra 4 on Voja for trampling commander damage is nice, but it's very expensive and I want to be in a dominant position by turn 6. Same with Feed the Pack. I love saccing a llanowar elf that has a ton of counters on it for a ton of wolves, but it comes online late. I could see dropping both of those for 2-mana token producers.

I try to keep up board wipe protection mana, because wipes are very damaging. Boros Charm, Flawless Maneuver, Rootborn Defenses, and Heroic Intervention together generally lets me see one.

Voja is pretty good at keeping the hand topped off on his own since the inclusion of the changelings. Having the draw on him has led me to pull back on other card draw sources for more gas.

I've considered adding a Concordant Crossroads to have the possibility of chaining mana dorks and attacking with Voja earlier for even more speed. I've also considered pulling the trigger on a Teferi's Protection to either swap out the Rootborn Defenses for or find another cut for a fifth boardwipe protection.