Darn right. Wouldn't be the first time Sakurai defied all logic with his posts.
Anyway, I interpret Sakurai's cryptic comment and Ness' chances thusly:
1)He asks if Lucas can surpass EVEN Ness. The key word there is 'even'. This implies that it's more than just Ness Lucas is trying to surpass, it's the rest of the Brawl fighters as well. Under this assumption, you can expand Sakurai's statement into 'could he (Lucas) surpass the other brawl fighters, even Ness?'
2)Replace the word 'Ness' with any other character name. If Sakurai had said 'can he surpass even Luigi/Ganondorf/Captain Falcon?' we'd all be cheering the near-confirmation of another returning character. We only think this means Ness is out because that's been a point of speculation which has colored our judgment.
3)It seems odd that Sakurai would replace a character and not be honest about it. After all, he was honest about Zamus not being a true stand-alone character, so why wouldn't he just come out and tell us if another character was being replaced?
4)The other interpretation of the 'Lucas surpassing Ness' question is that Ness has been surpassed and replaced by a better character. This is also odd. Remember, the tiers aren't an intentional part of smash. When Melee was made, Sakurai tried to make each character more or less on equal footing. Taking this into account, it seems odd that he would deliberately make a better character instead of trying to make a balanced one.
5)Yes, we all know that Sakurai was hoping to replace Ness with Lucas originaly. However, we also all know that Sakurai wanted Sigurd instead of Marth, and wanted Dedede in the first smash bros. Not everything Sakurai planned on happens, and after becoming a double veteran I doubt Sakurai would still give Ness the boot.
And that's my thinking on the subject. I'm sure not all those arguments are fully fleshed out, but I think enough of them work to make a decent point about Ness and his chances.
Oh, I'd also like to mention that Lucas completely blows all "Sakurai is only going to use international characters and won't touch Japanese-only characters" speculation out of the water.