I find it really hard to place MCU Ghost Rider in terms of power tier. He should be up there, but because AoS has a very limited budget in comparison to the films, we never see him duke it out with any real big league names. The most impressive opponent he fought was Ada, who he absolutely stomped, but she isn't exactly what I would consider an upper tier character. I mean yes, she was a powerful enough villain for AoS, but that's about it.