These "don't deserve to be Marvel Legends" arguments are so silly. We've been hearing them since Toy Biz made X-23, and they're just as tired as they were then.
If you don't want a figure, then don't buy it. But complaining about its existence feels so self-centered. As Damien said, every character out there is someone's favorite. Or at least has an audience.
I love when characters like Crystar/Warbow are made in the line. The random pulls. It makes the line and reveals interesting. Crystar was a Marvel property, so it's fair game. And the ML guys not only thought it was an interesting figure, they also probably thought of reuse for the body. Warbow is a companion piece to Crystar but is also a way to reuse Crystar's mold. Also maybe Martinex and an eventual Iceman can use that angular body. But I also think the ML team is just having fun. They're people too with different tastes and get inspired by a variety of sources. They're also artists, and these figures are essentially artistic takes on characters from a different medium. Not every character is going to appeal to everyone, and that's ok.
Cottonmouth’s boring head instead of one that displays his enlarged mouth powers
Siryn with no screaming likeness
These types of things are an issue. I like someone like Cottonmouth being in the line. But showcase his power with an open-mouth, elongated jaw head. Why not show off what makes him unique? While I don't want figures to only have a screaming head, an open-mouth head for Cottonmouth makes a whole lot more sense than a smiling one. Siryn as well. Her power are based on her screaming, so give her a screaming head. I also want to add one complaint...Skurge the Executioner not having a gripping left hand for 2-handed axe-wielding. I didn't like it when Terrax had that limitation, and I don't like Skurge having the same issue.
Pink Iron Man doens't take away from anything else in the line. It's a standalone figure. A way to recoup costs. Obviously, these holiday-themed figures work for Hasbro, or they wouldn't keep making them across their lines. Someone is buying them. If you don't like them, don't buy them. But don't bemoan their existence.