With this existing mechanical infrastructure in place, its not unreasonable that Host/Augment could come to black border
Alphinaud Leveilleur* 4 Mana for Alphinaud is a lot, given what else you can get in card draw there, and the fact its only on your second spell each turn combined with a poor size make this a creature you probably leave out of your party, unless you are wanting to make use of its partner
As I started going through more options, though, I realized that "essentials" here could mean things like Dockside Extortionist, Purphoros, God of Forge
For just four mana you can Form a Party by drawing the top five cards from your library and keeping any of the creatures that you find there
Weve seen poorly received mechanics be rehabilitated in the past, perhaps most famously with Chroma becoming Devotion (a technically weaker mechanic with amazing flavor), but weve not yet seen successful mechanics evolve gracefully into new mechanics
Its still fluctuating regularly, but its ahead by a long shot