I don't like it when roles are recast unless there's a REALLY good reason, but getting the Rachel Dawes character back with a new actress is better than not getting the character back at all (which is even MORE annoying than recasting).
I like Matt Damon, but I can't see him as Dent. Jamie Foxx, on the other hand, would, IMO, make a really cool Harvey Dent, not only because Foxx is a good actor, but also because, if cast, he'd be getting a chance to do what Billy Dee Williams should have gotten to do (play an African-American Harvey Dent/Two-Face). Edward Norton and Josh Lucas would also be great as Dent, but Foxx is my #1 personal choice out of those mentioned in the LR article.
Also, for what it's worth, Jett at BoF lists LR as a site he trusts.