The thing about that Miiverse post is that the poster really underestimated why we really love Shantae as a hero.
Yes, Shantae's childish, yes, she's naive, yes, she's even immature. But she's young. Yet, she presses on, no matter what. That is why I love Shantae as a hero.
When Shantae was tricked by Risky in the GBC original, with the magic stones stolen right out of her hands, Shantae chased her without question, and when Shantae was asked if she wanted to be a full genie, she declined, as she wanted to keep fighting and stay with her loved ones.
In Risky's Revenge, when Shantae sacrificed what she considered her greatest strength, her magic, to save Uncle Mimic, she didn't back down or run away, she stayed and fought nega-shantae as a human.
In Pirate's Curse, as a full human, she continued fighting, and now that she was stuck working with Risky, she tried to get on good terms with her, to the point where Shantae put herself in front of Risky, saving her life, in order to confront the Pirate Master, and even when Shantae lost the pirate gear, Shantae strived to win a battle that seemed to big for her.