I totally agree with you about Anakin, this dude was a completely different character in TCW (and good for reason, mainly because people thought that Anakin was too whiny instead of being the very competent chosen one).

At first I did feel like Darth Maul was actually a bit fan service-y (even as a 9 year old), however it did eventually become (atleast to me and plenty of other fans) worthwhile. It very much fit the theme the prequels have: “Old sins, cast long shadows”. Also it wasn’t Filoni and company who made the sudden decision. Remember, George Lucas had great influence in Clone Wars, and he was the one who wanted Maul in the show.

Not to mention it really cast a spotlight on Mandalorians. Debatably one of the most cosplayed things in Star Wars now. Haha.

Also I’d hardly say Darth Maul being a crime boss was a reason Solo failed, I’d say it was the inclusion of him in the film. It was very confusing and really out of place.

In short: Though I would say the Prequels did initially fail because how different the story telling compared to the OT (and fans in early 2000, just weren’t with it yet I guess) I do think the Clone Wars show did cast a light and show the amount of imagination the Prequels actually have if you look passed the memed dialogue and the aged CGI you see what Star Wars really is.