A web designer at American Airlines explains why a "simple redesign" of the website ends up being anything but simple:

But --and I guess here's the thing I most wanted to get across -- simply doing a home page redesign is a piece of cake. You want a redesign? I've got six of them in my archives. It only takes a few hours to put together a really good-looking one, as you demonstrated in your post. But doing the design isn't the hard part, and I think that's what a lot of outsiders don't really get, probably because many of them actually do belong to small, just-get-it-done organizations. But those of us who work in enterprise-level situations realize the momentum even a simple redesign must overcome, and not many, I'll bet, are jumping on this same bandwagon. They know what it's like.

You don't even have to be at a huge enterprise to have some of these things rear their head :)