Clone Wars did a great job portraying Anakin's gradual slide. There was nuance and plenty of exposure of the good parts of his character. His friendship with Obi-Wan was in evidence. His relationship with Padme was believable.

The fact that post-pubescent prequel-Anakin was ever trusted by anyone is at best evidence of how the dark side clouds perception.

In the prequels, from EPII he continuously felt like someone who should clearly be a Sith being shoehorned into being a Jedi. His friendship with Obi-Wan existed in name only, and his "romance" with Padme was in fact not a better romance than Twilight. (And that's saying something.)

OG fans waited decades to see Vader's backstory, and what we got was about the least rewarding most hamfisted and uninteresting portrayal of that backstory that could have been achieved. Decades of fan appetite regarding that backstory, possibly the only time such a thing has been maintained in the history of cinema, or likely will be again, and Lucas gave us Jar-Jar, cringe dialog, limp acting, and endless CGI.

D&D royally fucked up with GoT, but using the prequels to shine a light on that reads like something from The Onion.