The Eagle was a phenomenal aircraft in it's day, and has been a dominant fighter aircraft over the last 30 years. Unfortunately, it's just old. There's no amount of new avionics or modifications to the airframe that you can perform to make it really a dominant fighter now given what is currently fielded.

It can hold it's own currently, but it's certainly not the best in the world because of the airframe design. It's the training and tactics of the people that fly it that make it so.