Warning: Spoilers for Spider-Man: No Way Home
The Green Goblin returns in Spider-Man movies, by way of opening the Multiverse. However, despite Willem Dafoe's performance in Sam Raimi's original movie becoming an iconic part of Spider-Man lore, No Way Home opts for a noticeably different physical representation of the character.
In No Way Home, Peter accidentally alters a spell to erase the world's knowledge that he's Spider-Man being cast by Doctor Strange (Benedict Cumberbatch). This causes various characters from other universes who know Spidey's secret identity to be brought over into the MCU. Among them is the antagonist of Sam Raimi's first Spider-Man movie, Norman Osborn a.k.a the Green Goblin, with Willem Dafoe reprising the role.
While Norman Osborn initially arrives in his full Goblin suit, he later shatters the mask in a back alley while trying to get his bearings on the strange new world he's in. The decision for Dafoe's Norman to go mainly maskless in No Way Home can partially be explained by the Goblin mask itself. While Dafoe's portrayal of Norman Osborn and his Goblin persona in Spider-Man was widely praised, the rigid, unexpressive nature of Goblin mask (which is really more of a helmet) received its share of criticism, so No Way Home was likely trying to avoid a repeat of that. However, while the original mask had its share of problems, there are other reasons why removing it facilitated not only the drama of Dafoe's performance, but also more subtle aspects of the Osborn/Goblin character.
A key consideration is the fact that Norman, after his laboratory experiment in Spider-Man, was afflicted with the Goblin persona that now dominates his mind. No Way Home leans heavily into this, showing Norman fighting an internal battle in his head against the Goblin. Despite Norman's efforts to remain in control, the Goblin takes complete control over his mind during Peter's efforts to remove the different villain's powers in order to send them home without each meeting his death, specifically Jamie Foxx's Electro and Alfred Molina's Doc Ock. It would be a lot harder to convey a mental struggle between Norman and the Goblin with his mask on at all times, so leaving the mask aside helps show what he's going through much better.
That also leads to the third likely reason for the Green Goblin mask being destroyed early in the film, which is Willem Dafoe himself. Dafoe has a very expressive face, and as seen in both the original Spider-Man and No Way Home, is able to shift from Norman to the Goblin with just the subtlest of facial contortions. Dafoe is equally adept at altering his voice to signify whether he's playing Norman or the Goblin at any given moment.
While the Goblin mask served its purpose in Spider-Man of hiding Norman's identity, there's no real need for him to do the same with No Way Home. Combined with how chilling Dafoe is in Goblin mode and how powerfully he can show that with his face and voice, Norman going without his Goblin mask better shows how sinister a villain the Goblin is, and how even Norman has become a victim of the persona. Norman might have needed his Green Goblin mask in his origin story, but for Spider-Man: No Way Home, he's a much stronger villain without it.
