The issue with making that comparison is that Sakurai specifically said no anime characters. He never said, "No one-shot characters." Granted, yes, he could change his mind, but it's still something significant to note, yes? And while yes it is impossible to draw a line ourselves between what he is willing to do and what not, it doesn't follow that because he does something out of what he has done in the past that he is going to go to even further extremes or is equally likely to incorporate something decidedly more extreme than something that might be interpreted as somewhat extreme.
In fairness, the whole anime thing was an over-exaggeration to drive a point home, but yeah - I see what you're saying. Maybe I'm just jaded and skeptical due to the whole build-up to Brawl; everybody wanted
this character or
that character but at the end of the day, a lot of the character choices, bar a few, were the "obvious" vanilla choices, so to speak, rather than the curveballs (but fan-favourites nonetheless - remember when people thought Geno was a shoe-in?). Again as an example, there was widespread support for Zant, but in the end it didn't happen, and Ghirahim is effectively in the same boat, until the next Zelda game comes out that is.
Besides, the fact that the unincorporated characters is running out of juice might allow for a more liberal approach, perhaps to a small degree.
If anything, I'd say the opposite is true. The fact that many franchises didn't even get new reps in Brawl (Mario, Zelda, F-Zero, to name a few) speaks volumes about the decision-making process that Sakurai goes through - to me, it says that Sakurai would rather not give a franchise another rep at all than add a character who he does not feel is prominent enough to warrant a spot over other
"more important" (in his eyes at least) characters. Whether that remains to be the case in SSB4 is still up in the air, but I shouldn't think it's too illogical to think he'd want to exhaust more iconic characters and ones from as-of-yet unrepresented franchises before he gets around to one-shot characters like Ghirahim.
Not to mention, it's been heavily hinted that SSB4 won't have as much newcomers as Brawl did. I imagine they'd want to use every newcomer spot wisely provided this is true - in a way, it's less that Ghirahim is
undeserving so much as there are far more deserving characters
'competing' (in a purely metaphorical sense) for those roster spots and the teams development time. For each small-time, one-off character like Ghirahim, there's one less hypothetical roster spot for vanilla 'all-star' characters like Pac-Man, Toad, Ridley, etc. etc.
(Disclaimer: I'm not in any way saying that Pac-Man, Toad or Ridley will be in or even DESERVE to be in, that's a different topic for a different day)
In the end, isn't that kind of what it is? We can try to make logical arguments about why a character would be represented over others, but we'd simply be pretending to know what is going through Sakurai's mind and the even more unpredictable variable of what he's been testing and hearing in his progress. And who is to say that Sakurai is uninterested in what the mob of fans have to say about what they want?
I can completely agree with this. Sakurai's an oddball, I'll give you that - to truly make educated guesses we'll need to see a first trailer of SSB4 to see what direction they're actually taking the franchise in. But for the time being? We can only make do with trying to use Sakurai's past (albeit somewhat inconsistent) patterns when it comes to guessing how the roster will expand. But you know, I'd love to be proven wrong by the Smash team, since there are plenty of 'unlikely' characters (Eggman, Simon Belmont, Suicune, Jimmy T., King Boo, the list goes on) that I'd love to see in Smash. For the mean time though, you could say that I'm keeping my guesses conservative, since we have no indicator so far that Sakurai's methodology for choosing characters will be much different to how it was in the last few titles.