Well, no, he's right, "up until now", on its own, describes the situation in the previous two Smash games. It COULD potentially show a change, but it doesn't do so automatically.
Take, for example, handicaps:
He doesn't say anything in that sentence (and ONLY that sentence, you can't say we were meant to look at the entire update to figure out the meaning of it) that directly hints toward a new system, just that the concept of handicaps is returning. He could have just as easily ended that sentence with ", and they are returning in this game.", then went on to explain the handicap system, the same way it was in 64/Melee.
The thing is, though, the Lucas/Ness situation and the handicap situation are a bit different from each other. With the handicaps, we were actually told the system had changed, and every detail was laid out. With Lucas/Ness, however, we've only been told Ness was in the previous two games, and nothing else, which gives us incomplete evidence. Sakurai could either introduce Ness at a later date, or, going by the prevailing meaning of "up until now" around here, deconfirm him by players getting the "You have unlocked every character!" notice with Ness not on the roster, among other methods.
