"I think there is too much focus on the Grand Slams these days which isn't fair", said Federer.
Frenchman Pierre-Hugues Herbert, a grand slam victor in doubles who was targeting the ultimate grass-court singles scalp, proved no match for the Swiss master and fell to a 6-3 6-3 defeat.
37-year-old Federer has struggled for rhythm throughout the competition, dropping sets to Jo-Wilfried Tsonga and Roberto Bautista Agut, but he clicked into gear when he started to dominate Goffin, breaking three times in the second set.
Herbert won the first set of his quarterfinal 7-5 against reigning champion Borna Coric, before the Croatian retired with a back problem.
The world number three swarmed all over his 33-ranked opponent in the second set, Goffin's serve getting him into trouble.
German Zverev served nine double faults as he lost 3-6 6-1 7-6 (7-3) to Goffin.
Goffin now stands between Federer and his 10th trophy at Halle - the first time he has won 10 titles at a single tournament.
Lopez was the second 37-year-old to win an ATP tournament on Sunday after Roger Federer claimed his record-extending 10th Halle title. "It feels great. So I'm very, very happy clearly". He's won the title 10 other times. "I wouldn't have done anything differently, apart from the mistakes I made when I was younger which we all make".
Federer has had a promising year thus far, with victories at the Dubai Open (ATP 500) and Miami Open (ATP 1000), as well as encouraging performances on clay after a three year break from the surface.
Barty showed little sign of the arm injury - the same one she had going into the French Open - which saw her pull out of the doubles on Saturday where coincidentally she was partnering Gorges.
Goffin falls to just 1-8 against the Swiss.