>>150335446
It is part of Maka's character arc the fact that she is weaker than Black Star and Kid, this is hammered over and over again during the whole manga, and is the source of Maka's insecurities.
She overcomes this not by out muscling Black Star and punching the big bad guy in the face but rather by leaning into her own strengths, learning new abilities, unlocking the full power of her soul, turning Soul into a Death Weapon, and working hard.
Even in the final fight Kishin Ashura recognizes Black Star as something beyond humanity, Kid as a true Shinigami, but Maka as just a pathetic human that shouldn't be around him.
Don't get me wrong, Maka is weaker than her peers but she isn't a glass canon or just a support.
As I said she survived direct attacks from Kishin Asura without her Black Blood Armor, could keep up with Crona using a heavier weapon, and in the end it was thanks to her that the big bad guy was sealed (and to do that she needed to hurt him twice to enter and exit his body)

>>150285009
BlackStarfags are extremely insecure and since Kid is both stronger and a better character they choose to pick on Maka who at least is canonically weaker.
The Mangaka made Maka repeat time and Time again how strong Black Star is compared to her but since after Mifune the guy is just an NPC that fights without any arc or character development, while Maka gets multiple amazing moments to show her growth and determination, they feel the need to lash out.

>>150257246
>>150257261
She's not a Mary Sue, her whole deal is being a smart and hardworking girl who's limited by her own strength and insecurities.
I think she's fairly well written, specially if we compare her to modern shounenslop MCs.