"By including these 12 characters on the disc, the idea was to ensure easy compatibility between players who do and do not choose to download the characters when they arrive as DLC."
We're too lazy to try. (This is actually very easy, SR3 handled it perfectly)
"The update also saves on file size - instead of a massive download, there will be a much smaller unlock that brings the new content to the surface."
Bad cover up.
"This move also furthers our desire to avoid a "Super" version of the game down the road. Everything you need to enjoy this game for months (and years) to come will be accessed by the retail disc available this week."
Shouldn't be so greedy in the first place.
"While Capcom is sorry that some of its fans are not happy about the chosen method of delivery for the DLC, we believe that this method will provide more flexible and efficient gameplay throughout the game's lifecycle. There is effectively no distinction between the DLC being ''locked'' behind the disc and available for unlocking at a later date, or being available through a full download at a later date, other than delivery mechanism."
They're not sorry.