After much discussion in the group about the direction of affinity / artifact decks, I've decided to make the following changes. I've been somewhat vocal about disliking narrow cards, so I've tried to keep things like Master of Etherium to a minimum. A lot of these cards I am somewhat suspect on (Securitron Squadron, Springleaf Drum), but others are cards that have been in before and I think are still reasonable.
Similarly, I have decided to reintroduce Hardened Scales and a +1/+1 counters package. I have a Steel Overseer / Hardened Scales fantasy that I want to live out, and I am hoping that revitalizing the artifact package will bear fruit in this respect. Again, I tried to keep the deck-specific cards to a minimum and include cards that are generally good. I'm interested to see Nadu play with the wealth of luminarch aspirant effects that are now present.
Regarding cuts, I've made a lot of like-for-like swaps, as well as cut some narrow 3-color cards. There are some classics that have been put on the block (Winter Orb, Shinobi), but I am very happy to bring these back at some point. I know these cards are good and can reintroduce them at any point.
Going all-in on lots of discard effects, Master of Death seems like a good card to bring back. Much better than Squee or something I think, and is a zombie as well.