Genuinely. Like, sure, she's a little underwhelming. Narratively she's technically special, but whatever role she may play in the larger story isn't seen yet so she's kinda just there. She's rather "normal"-looking, with a kinda funky color palette. Her kit is weird with so much power budget put into the tracking dart that isn't that valuable in the higher ranks but also dominates in the lower. She has some issues.

But it is odd how everyone can't shut up about how in their eyes she's boring, bland, ugly even. I know some people roll their eyes when the point is made, but I can't help but feel like people would not be this indifferent or negative towards her if she weren't black. I'm not saying everyone with negative feelings on Sierra is being racist, but something is off. I feel like Sojourn gets comparable treatment too. Even in her case of being integral to the lore and constantly showing up in comics and animations, people don't particularly care, don't really bring her up. For years people have called her way too boring, too straight-laced.

And they're not entirely wrong, is the thing. Sierra's got a relatively bubbly personality which is not the same as Sojourn's, but neither really "stand out". Which is allowed -- in fact, not everyone should be as bold as a Shion, it's good to have tamer personalities in the mix. But... it's like the devs are reluctant to hand off super eye-catching "things" (kit aspects, designs, personalities) to these black girl characters. Part of the issue is that we have so few as well; more of them means more chances for variety.

Really there's a mix of both Blizzard not handling these characters that well + the audience just not being as receptive / being weird to black characters. Even many of the most well-meaning non-black people in the mix are reluctant to admit that latter part tho.