Friedel is not better than Gomes...what Friedel is is more reliable at the basics, meaning the defence in front of him can relax a bit, and not be filled with constant anxiety if, for instance, they have to pass the ball back, under pressure.
Ultimately, what it means is that Gomes will concede net more goals than Gomes, but the team will concede net less goals with him in it.
With Gomes he is more effective in turning defence into quick attacks. Frediel's distribution of the football especially his kicking is hopeless. He is reliable if there isn't a difficult shot to save. Frediel has aged and is no longer the same keeper as the one some years ago.