Speaking as someone who only entered the magical world of comics about five years ago, Wikipedia is a new reader's best friend. Yet I remember my frustration after reading a lengthy article on a character's history only to have to run into something called Crisis on Infinite Earths. Having to go back and figure out which parts of the character were changed was a bit of a headache. Eventually I stopped reading a characters Pre-Crisis story and just skipped ahead. If the DCnU is about accessibility, then shouldn't the characters and their history be less complex, instead of more? I'm picturing the new reader of the future trying to read previous stories of a hero I enjoys and running into Pre-Flashpoint continuity, some of which matters and some of which doesn't. Picture the new reader trying to get a backstory on a character and hearing about stories that still happened except for Character X no longer existing. And I thought Crisis was confusing!
On a side note, DC still hasn't said whether the Multiverse has been changed by Flashpoint or whether only the "main" Earth has been changed. We do know that Grant Morrison is continuing with his Multiversity project so I think we can assume that the Multiverse still exists in it's entirity but that's pure speculation.
If DC wanted to update their characters, how bout doing it the Marvel Way? Marvel subtly slides their characters origin dates forward without making a mess. Which war did Tony Stark get captured and become Iron Man? It's moved from Vietnam, to not a war, to the Gulf War. They're slowly updated their characters and yet no one really complains about it. I can see why DC might not go this route, their characters have become so symbolic and so iconic that it's hard to make subtle changes. Look at Grant Morrison's work on Batman. Everything from the bell that Bruce uses to call Alfred after his first night of crime fighting to the movie that he watched with his parents has now become an important part of Bat-history. Try updating that!
In my opinion, a soft reboot is nice and comfortable in theory but for a company like DC Comics, they have to go with a hard reboot, or no reboot at all.