1) There is no evidence in the game to suggest that Vayne honestly wants to change the world for the better. Every character in the game sees through this as a facade for his quest for power - the judge magisters in the scene in the halls of Archades, his own father when talking to Gabranth, Bergen admires him for it, and Venat and Cid would not have manipulated him if he did not possess this quality above others.

2) Even if you could find deleted scenes which prove that he does believe in it - it does not make murdering his 2 older brothers to become successor any less evil. Nor would it make poisoning his father any less evil. Or ordering the murder of the head of Ivalice's religion and the slaughtering countless innocent refugees. Nor would it make ordering an entire city to be wiped out, or endangering countless more innocents than you have already killed with a final battle.

No righteous attitude can make the causing of mass suffering any less evil. Our own history has attested to this many times throughout. This is also the main theme of the game - the conclusion which the protagonists come to at the end.

I have continuously cited evidence from the game in my posts, and have yet to see any from anyone who disagrees. If you still do, I will respect your opinion, I only hope that you can respect mine. If anyone cites evidence from the game, I will gladly look at their arguments and even concede if a better one is established.