Metroid isn't that popular in Japan, but it's popular enough- and big enough -that two characters is not unfeasible. I suspect the fact that we've only had one character so far is less about series popularity and more a lack of an obvious candidate outside of Ridley.
Three or more characters is unlikely though, even if it had many obvious candidates. I think part of why Star Fox got three was that it was easy enough to add in more since all the characters are fairly humanoid, armed with advanced weapons, and their animal qualities give them some melee options. So it was easy to implement Wolf for a quick roster addition.
edited 23rd Jan '14 2:42:57 PM by Anomalocaris20
You cannot firmly grasp the true form of Squidward's technique!![]()
Pretty much this.
It's nice we finally got a second Metroid character in Brawl, but we could easily have one more. And I prefer something other than a Hunter or Dark Samus. Main reason is that it still reminds me too much of Samus, a big suit-wearing badass with a gun. Zero Suit at least changed it up design-wise, but didn't much change it overall(well gameplay yes). Still a similar idea.
This is why I want Ridley, to have something far different.
Shadow?I'd say Ridley is more iconic than Mother Brain, personally. He is Samus's archnemesis and is The Heavy in Super Metroid, he's just never the final boss. Not to mention there's only been three games without Ridley (Metroid II, Metroid Prime Hunters, and Metroid Prime Echoes, the latter of which was actually going to include him), whereas Mother Brain has only appeared in the original and Super Metroid, and during the opening of Other M.
He's also the only boss, aside from Dark Samus in Metroid Prime 2, to be fought more than once in a game, being fought twice in Super Metroid, Metroid Prime 3, and Other M (Also, Zero Mission has the robot Ridley in addition to normal Ridley).
edited 23rd Jan '14 3:17:25 PM by Anomalocaris20
You cannot firmly grasp the true form of Squidward's technique!...He's ALWAYS been an important boss. Except maybe in Metroid and its remake. In Metroid Prime he's essentially the main antagonist you chase to Tallon IV, and the penultimate boss. In Metroid Prime 3 he's fought twice, once in a climactic falling battle and again as the penultimate boss. In Super Metroid he's the Hopeless Boss Fight and the penultimate boss. In Other M he's... well, a role in a very "special" scene, and probably the only boss they put any effort into. In Fusion, he's yet again the penultimate boss, and even gets some buildup unlike most of the others.
Heck, he's even the penultimate boss in the original, but there were only three bosses there and he was no more important than Kraid back then.
edited 23rd Jan '14 3:22:23 PM by Anomalocaris20
You cannot firmly grasp the true form of Squidward's technique!Ridley is the first and penultimate boss of Super, one of the main antagonists of Prime 1, the final boss of Zero Mission, the second and penultimate boss of Prime 3, and had one of the biggest scenes in Other M. Mother Brain is the final boss of Metroid 1 and Super Metroid, but she only leaves an impression in Super.
In short: Ridley is more iconic among fans. Mother Brain is more iconic among non-fans. My first game was Zero Mission, so I more readily think of Mother Brain as the main villain. I never finished it, mind you.
edited 23rd Jan '14 3:23:57 PM by doctrainAUM
"What's out there? What's waiting for me?"...Ridley is never important? Maybe in Metroid, where he is just a boss like Kraid, but in Super Metroid, he was the one who captured the Baby. In Metroid Fusion, they make a showing of the frozen Ridley (clone corpse) early on, which leads to one of the late game bosses much later on. Zero Mission had a whole cutscene around his showing up and such (plus he got a robot!).
Also, Metroid Prime stuff.
And that is not even going into backstory and lore stuff.
edited 23rd Jan '14 3:25:12 PM by Otherarrow
Don't PM me. We don't like being PMed.Trophy description of Ridley in Brawl:
"The leader of the Space Pirates. He looks like a pterosaur but has high intelligence and a brutal nature. He plans to steal the baby Metroid from Samus for his own use. Ridley utilizes wings for a full range of flight and attacks with fireballs from his mouth and whips of his tail. As the culprit behind the murder of Samus's parents, the connections with Samus run deep."
In addition to the highlighted I don't even think Mother Brain got a trophy in Brawl whereas Ridley is called their leader and he gets two boss fights. I think it's obvious that Sakurai considers him the primary antagonist.
edited 23rd Jan '14 3:28:27 PM by Kostya

Honestly, cool as Ridley would be I doubt he has a chance of getting in.
As beloved as the metroid series is, japan doesn't really like it too much.
Much as it pains me to say it, I'm fairly sure that we're lucky to even be getting Samus.
(That being said, I would prefer Dark Samus. I would totally main her if she got in.)