Some random thoughts:
This is the only card that gives you card advantage without costing you a spell slot.

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White had too many good 1-drops, making it too easy to draft aggro. I'm getting Giant Killer back in, because a tapper is unique, the spell is interesting too and it's playable even when it's not ideal.

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As far as aggro artifacts go, density is more important than actual quality. The goal is to play power cards like Cranial Platting, Steel Overseer or Arcbound Ravager so the disruption offered by Phyrexian Revoker seems more valuable now than the semi-synergy of Syr Ginger. It's also a much cleaner card.
Besides, I've always found the whole "Syr" thing to be kind of cringe.
Adding this has been a huge success. It's early interaction, which is exactly what green lacks. I like that it's limited to 3 mana or less and it doesn't exile, I feel it would be too much of a silver bullet otherwise.
These cards are a bit narrow and not too great so I ended up cutting them long ago. Yet, I think I made a mistake. Without these type of cards, the aggro human deck simply lacks a reason to move into WG and WB. The moment I put them back, I started to see decks on those colours again.
Champion is a bit binary, but its ability to close games make it both different and enough of a payoff to justify its 1GG cost. It makes you want to draft equipment in green, Mutagenic Growth or Berserk, all of which makes the cube better overall.
Xathrid Necromancer isn't always better that Midnight reaper, but it s a human-lord and both WG and BR decks can make use of him. It's also a different kind of effect, which is something I value. Given I have free slots, it's well worth the addition.
Unlike Master of Death, which is a decent creature on its own and has relevant creature types, Squee is pretty bad. But I've found it necessary to use Bazaar of Baghdad and provide redundancy. I would replace it with something else, but there are only two creatures with this "return to hand" effect.