Mr. Saltman said:
I don't really like Birdo that much. She's very ugly and not as "cute" as others think she is. I also think SMB2's other characters deserve more reappereances than her (yes, even Clawgrip, the poor sidestepper no one talks about anymore).
I thought it was fine for her to be in SMB2 because the game was supposed to have super weird dream-like enemies, and a pink dino shooting eggs through his mouth was fitting for that. Now she just tries to be cute and I don't see her being in subcon or being that evil anymore.
Maybe they made her appear more because they needed a grilfriend/Female counterpart for Yoshi idk.
Another opinion I think is unpopular: I think Geno is overrated. Yes, he's neat and his weapons are cool, but I'm not really in love with a guy who appeared in a short as heck game full of characters that appeared in like 10 seconds. I felt like Mallow was more developed because he had to do more things than him and has a better backstory behind him. He's the real underrated guy from that game (even if I'm not a big fan of him either). Geno didn't really have much of a backstory or anything because all what he did was talk about the stars and Smithy, and nothing else.
This is all just my opinion though.