Part 1 here
Part 2 here

White

I was already happy with most of what this color is doing so there are only a few changes here. I love the valiant mechanic from Bloomburrow so I'm bringing back Virtuoso and adding some mice to RW. Phelia I feel might be too strong for this environment with her ability to reset counters and delete blockers but I already have her so I might as well test her. With some good ETB targets in white she might also inspire a blink deck at some point.

Blue

Blue gets the fewest changes out of all colors and most notably trades two creatures for spells. Pteramander once again replaces Cloudfin Raptor for what feels like the third time. Malcolm, Alluring Scoundrel is moving out since I was never a big fan of the added complexity of his chorus counters. Plus, I felt like with a curve this low, by the time you get to four counters, you don't particularly care that you can free cast the card. Kitsa and Shoreline Looter are filling the same mechanical space with more interesting and less complicated text respectively.

Multicolor

For overall archetype changes see part 1. Most importantly, moves from full control to a tempo gameplan and moves from big guy stompy to a slightly lower curve with a cast-from-exile subtheme. All colors gain some additional themes which is reflected in many of the new signpost choices.

Colorless & Lands

The colorless changes focus on more artifact buildaround support plus Pip-Boy 3000 which I'm excited to try out. With the revamp of and Crashing Drawbridge no longer fits, and Lucky Clover goes along with the rest of the adventure matters package.

In the land section the biggest change is the move to fetchlands which replace all of the Thriving lands and those other random 5c fixers. Restless Ridgeline replaces Raging Ravine to avoid misunderstandings with double activations. There's also Talon Gates of Madara coming in which seems great.

At the top of the watchlist right now are all of the planeswalkers. I'm not happy with Liliana, Waker of the Dead since she doesn't really interact with combat except by removing stuff. Mu Yanling, Sky Dancer makes very large tokens and Archangel Elspeth creates tokens on + which is why I'm having an eye on these too. So far planeswalkers haven't been a problem but I'm also reconsidering what my goals are for these in the long run.

Besides that, with a space set coming up and sci-fi taking a much larger role in current releases, I've been toying with the idea of splitting sci-fi themed cards out of this cube to keep this one themed as fantasy-Eldraine-Bloomburrow-like and have a separate sci-fi-space cube longterm. But that's definitely a question for next year.