Really glad you’re getting value out of it! I’m glad you enjoyed Duchess, that one had a very technical cut in it to get rid of a super goofy element that I’m proud of.

Assassin is a hard one to enjoy as it’s not super strong, but it does give some early Ahsoka and Ventress that develops both characters. And you’re fine to drop the 501st if you don’t mind skipping some more competent villains.

Geonosis’s first ep isn’t vital as it’s largely Padmé doing some politics, but the other two are fun, especially the worms one, with more good Ahsoka. Plus it introduces an important character who shows up a few more times and is important to Ahsoka. Onderon is also not super vital but it does show an early attempt at creating what essentially grows into the Rebel Alliance.

If I had to recommend an absolutely super tight truncated order (which I wouldn’t recommend, but it’s viable) just to focus on getting through TCW very fast and not necessarily hitting all the major character development or popular battles, but covering the main beats specifically for the Clone Wars characters’ story, it might look like:

s00e01,02,04 [TOTJ] Justice, Choices, The Sith Lord
s01e01 The New Padawan
s01e03 Duchess of Mandalore
s01e07 The Death Watch
s01e08 Children of Night
s01e09-10 Holocron Crisis arc
s02e02 Retribution
s02e04 Like Father Like Clone
s02e05 Monsters
s02e07 Tales of the Lost Clones
s02e09-10 Geonosis arc (without the setup)
s03e01 Politics of War
s03e02 The Death of Obi-Wan Kenobi
s03e03 Pirates of the Outer Rim
s03e04 Temptations
s03e06 The Shadow Collective
s03e07 Hunted
s04e01 The Old Ways of Mandalore
s04e02 The Living Force (some love this, I don’t, it appears to be becoming more important)
s04e03-04 Ahsoka’s Fall arc
s04e05 Deliverance
s04e07 The Renegade
s04e08 The Legacy of Sifo-Dyas
s04e09 Son of Dathomir
s04e10 The Cosmic Force
[Revenge of the Sith]
s05e02-04 The Siege of Mandalore arc
s05e07 [Rebels] Coda: Old Wounds

I’m sure many would disagree with some of the inclusions/exclusions here though.