In this post we see how one person underestimates Lucario's popularity.
No, I'm not underestimating his popularity.
I'm simply pointing out why he was added and why he may very well be replaced by w/e new Poke GF wants to push for the 5th/6th gen that could and should be in for the exact same reason Lucario got in. (To show off the new gen and promote it)
I'm not fully convinced the 6th Gen of Pokemon will even exist when Smash 4 comes out. Smash 4 could come out as early as Late 2013, and I don't see the next mainline Pokemon before 2014. So saying that we'll have two new gens of Pokemon by then is kind of a longshot.
No, it's not a long shot.
Saying Smash 4 will get out there by this time next year is reasonably hopeful wishing. But looking at the current state of Pokemon, the pace at which the anime is moving, the fact that they have been cramming legendary Pokemon into these movies and the anime which leaves Genosect as the last one get a movie in the next year and looking at the general time line of game releases ... yeah, many people are expecting a new gen revealed and released in 2013.
The reason why I don't see Lucario leaving is because the character has proven to be popular after all these years. I can't think of a single 5th Gen character that deserves the spot more than him. Everyone says Zoroark, and I don't doubt GF tried to make him the "Lucario" of the 5th gen, but in the end it kinda backfired, because Lucario certainly stood as the more popular Pokemon while Zoroark was just kinda... there.
And if GF has a say in what happens to Pokemon in Smash (which I don't doubt they do), then I'll say Lucario has a pretty big chance of staying. First, Lucario is prominently featured in some of the B&W2 anime promos for the game, even moreso than Zoroark. They also moved Riolu from a character you get in late/postgame to a character than can be captured before the first gym. Almost everybody is using Lucario in B&W2.
I'm not saying Lucario is a shoe-in for Smash 4, but I certainly don't think we should take his exclusion for granted. We know very little of the game's development and what Sakurai intends to do with it.
As for Fire Emblem, I think that series could use three reps. It's one of Nintendo's longest running series and it just got a popularity boost in Japan thanks to FE 3DS. Ike could easily stay alongside Chrom.
But you, for some reason, seem sure that there wont be a new gen revealed or released before Smash 4 comes out. I'm asking, what if that happens? What if we get a gen 6 Pokemon game revealed and released before Smash 4 comes out? I'm sure we can all agree that Lucario was added in to rep the "latest gen" at the time, much like Ike and Pichu. Would Lucario transcend his role and just be in "because ...?" or would GF and Sakurai look at things and say "hey, 2 new gens of Pokemon have come out between brawl and now. Lets swap out Lucario in favor of w/e new anthro looking Pokemon being used to promote the current gen as to pass the torch and highlight these new gens"?
I mean, damn ... Pichu's still used to promote tons of stuff be it in the form of the anime, toys/ merchandise or games years after it was used to promote the 2nd gen ... but I'm sure we can all agree we don't expect a Pichu return. It's not an effective rep for any gen outside of the 2nd, just like how Lucario is simply not a 5th gen or 6th gen rep.
As for FE getting 3 blue haired swordsman ... I would hate for that to happen. I said it before, it's like only using Pikachu and different gen versions of Pikachu to rep Pokemon, it's so limiting it pains me to think of that. The series is so big and interesting that if it ever gets more characters than 2 it should atleast use characters that highlight how diverse the units are. A lance/ axe/ mage character would far more interesting. Heck, a trickster/ hero/ warrior class character would be pretty interesting.
But, with that said, I simply expect any character that reps "the latest" to be replaced by some other character that can rep "the current latest".