Fans didn't really view the Vaive trade in the same way they viewed the Neely trade... and even the Neely trade didn't become "The Neely Trade" in Vancouver until he really caught on fire in Boston and it was clear we were dealt damaged goods. Williams potted 35 goals in his first full season and became a fan favorite in Vancouver, with the SCF run cementing his legend in the minds of the fans. I don't remember anybody complaining about it back then, and certainly never to the level of the incessant whining about Neely that went on for years.
It's interesting to wonder how well the Canucks would have done if Vaive and Derlago hadn't been dealt. When Jake Milford became GM, suddenly the Canucks had a competent manager, and the quality of drafting and talent acquisition went up immediately. After limping through the 70s, somehow we leave the decade with a young core more talented than any we'd had before: Gradin, Smyl, Fraser, Hanlon, McCarthy, Vaive, Derlago. 79-80 season saw the line of Fraser-Gradin-Smyl come together as the top unit under defense-conscious coach Harry Neale. Neale saw this unit as the future of the club. Vaive and Derlago, in contrast, had consistent problems that season, with Neale finally getting frustrated enough to call them out publicly for lack of effort and not backchecking. Captain Don Lever publicly went against Neale and defended them, so Neale had Vaive, Derlago and Lever shipped out.
So how does it impact the team if they weren't dealt? Well, the Gradin-Smyl unit stayed married as the top unit for four years before starting to slide to second unit status. Assuming they pick up their work ethic and win over Neale, Derlago-Vaive might be wedded as they were in both Vancouver and Toronto, what would that mean? Well, unless they started to seriously outplay Gradin-Smyl, they would've risen no higher than the second line, likely meaning that Vaive wouldn't have hit 50 goals as a Canuck. How would the Canucks have been composed in 82 for the playoffs? No Williams. If Lever is still here, no Rota or Boldirev, no Rota playing with Gradin-Smyl for his record-breaking season, possibly no C on Smyl or McCarthy.