Ma Chao did not suck. Please don't get me started on what will get me arguing for a long time
. Chen Shou left so many blanks there that had Ma Chao gone to war in an M1 Abrams tank and Tomahawk missiles, we wouldn't have known it
. He also himself expressed bias against Ma in the bio, so you have your answer right there. Jiangji's notes about Chen Shou are excellent in particular, so read on there.
Ma Chao seriously destroyed Cao Cao's armies in brilliant and great strokes four times. Jia Xu's brilliance saved the day (or Ma Chao's lack of a Jia Xu of his own). I argued similarily with Sima Yi as inferior to Zhuge Liang, and I will argue with Ma Chao vs. Cao Cao. If Ma had Cao's resources (strategists in particular), there would have been no contest. He was unstoppable on the field. He was the superior warrior and general, and Cao's generals and warriors (save Xu Zhu) could not match him. And honestly, do you blame him for not wanting to try to capture Cao Cao with Xu Zhu staring him down (he would have tried it had Xu not been so alert)? Xu Zhu in battle matched Ma Chao in skill, something no other could do.
"I have gained this by philosophy: that I do without being commanded, what others do only from fear of the law." -Aristotle