That's the thing though mate. We have a FAR vaguer idea with regards to this than we do the lottery. The UK lottery is solidly locked to 49 balls. 83 will never and can never show up. That's not the case here.
Except we don't have to have a specific, perfect combination. That takes all the guesswork out of it.
Given that we are not Sakurai, we have no idea what his criteria is for choosing certain characters, and can only justify them using hindsight, which people will do to infinity to invalidate the argument. We didn't guess ROB, we didn't guess G+W, and we didn't guess WFT.
I'd like to think by now that Sakurai's eccentricities should make him more predictable. Yeah, no-one guessed Game & Watch 'cause no-one really knew what to expect from Sakurai. Everyone assumed that, y'know, when you're making a Nintendo ALL-STAR fighting game, you're gonna focus on the all-stars first, but I digress. ROB only really wound up getting in 'cause he was essentially the centerpiece of Subspace Emissary. Could argue that if we didn't have SSE, we likely wouldn't have gotten ROB.
As for no-one predicting WFT, we have about three or four people that have predicted WFT, even if it was joking or in passing, so that proves that people HAVE considered it. I'm sure more people predicted G&W and ROB, though.
These characters are anomalies that highlight our inability to understand the decision making criteria, given out lack of involvement. So, by that standard, our odds are far, far worse than any lottery the world over - these anomalies exist, and are limited only by Nintendo's back catalogue, which spans the thousands. There are far more 'balls' in this machine than in any lottery, as has been proven by previous anomalies. Our odds are abysmal when compared to the lottery.
I don't find ROB, WFT and G&W to be 'anomalies'. They all share a common thread: they were important to Nintendo's success in some capacity, even if not necessarily relevant at the time when the Smash games were made. ROB almost much single-handedly saved the Nintendo and started Nintendo's good fortunes in the video game industry. G&W was all about Nintendo's foray into handhelds and LED's; if we didn't have G&W, we wouldn't likely be playing 3DS today. WFT encompasses a lot of what made the Wii special; the interactivity. Yes, it's easy to say in hindsight that these characters are obvious, but at the same time, they SHOULD have been guessed.
But, as I said, people weren't predicting these characters because they were focused more primarily on actual relevant, popular All-Star characters. We didn't have any idea how eccentric Sakurai was 'til Brawl's Dojo opened up, and even then, we didn't think it'd actually affect the roster.
To expand on my point, I get your point that some of the potential characters are 'easier' to figure out. Sure they are. A character like Ridley, for instance, would have relatively high odds. Our general pool of possible characters is probably around 50 at maximum, which allows for the comparison to the lottery.
Well, technically the pool is about around fifteen characters, which narrows it down even more, but I'd say the odds of successfully figuring out the final roster in any combination are still far better than nailing the winning numbers in the lottery.
Our big problem is the outliers. The ROBs, the G+W's, the WFT's. We assign rhyme and reason to these in hindsight, but our inability to guess them before announcement is proof that the pool for said characters is far, far larger. An argument can be made that such an off-the-wall character is included systematically in each game, effectively creating a secular pool for said character that expands into Nintendo's whole back catalogue. It's said character that makes the odds of nailing on as many characters as Sal has astronomically unlikely.
I think a lot of the reason why no-one considered guessing them are simply 'cause Sakurai's a far more eccentric guy than people gave him credit for. Like I said, we had no real idea how eccentric he was 'til Brawl's development and by that time the Dojo popped up it was too late. And if the odds of guessing the characters were as astronomically unlikely as people have made it out to be (in fact, I'm fairly certain that's a grave exaggeration on someone's part), then how come Sal's leaker did it? Everyone guessed all the other characters fairly easily. It was just Wii Fit Trainer that was the curve ball they swept under the rug. I don't find it to be 'astronomically unlikely'. More.. difficult to do given the information we had (which was pretty much none).
