Since we first saw "young Ani", I thought that we should see an older version from the start - he could be younger than Luke or even some years his senior - but at least about Obi-Wan's age (this would fuel the rivalry between "brothers" later ...)

Not sure if he should already be in the Order, just "overlooked", and be "found" by Obi-Wan, who not ready to be Master, takes up training him as his student - Anakin could also be (as some have suggested) a spice trader, smuggler type like Han, which would reflect some interactions with the scoundrel ;-)

The "leitmotif" should be: the road to hell is paved with best intentions!

So we have these different characters, from all ranging cultures and social positions, the hub is Plaplatine, who knows of their secrets and flaws ...

For the "big secret" - one could leave the "Vader transformation" offscreen - that isn't so bad ... on the other hand, we could lay some red herings, like turning Darth Maul into General Grievous (I try to make some mockups how "Darth Grievous" could look onscreen)

The other thing I wish to change is how Sidious is introduced: to keep a little suprise or make a greater impact in Episode3, Palpatine could be just the "nice old man" until he drops his mask in the final act.

Other road could go like this: we know who Sidious is, no smokes and mirrors, only the characters stab in the dark about this "mystery of the Sith" - so we cringe at every "wrong" decision that they make, only to see the inevitable end ...