Re: In hindsight what changes would you do
I think Rachel having girl next door looks is sort of part of the character. Bruce Wayne is someone who can pretty much have his pick of any of the hottest supermodels in the world, but he longs for his childhood sweetheart probably because of the innocence and purity she represents to him (a time before his parents' murder). Maggie definitely didn't have the right look for that though.
I would have personally enjoyed Rachel McAdams in the role. And yeah, Kate Beckinsale is...yum. She's more Selina Kyle material IMO.