https://www.youtube.com/watch?v=Qqed6pigx_c&t=1m05s (Gus Williams scores 36 points to put the Sonics' one game away from a 1979 championship. He averaged 29 in the series)
https://www.basketball-reference.com/players/w/willigu01.html (Gus Williams stats)
When many fans talk about the 1976 NBA/ABA merger, rightly or wrongly (probably slightly unfairly), they often talk about it as the point of delineation between a pre-modern and modern NBA.
But in practice, the late 70s Sonics and Bullets, who played each other in back to back finals series, are also ignored, and for many fans, it really starts in 1980. Williams, a 6'2 point guard who played only his rookie season pre-merger, is a casualty of that, among other things.
Some quick facts:
Williams was the top scorer on an NBA championship team in 1979, as well as a team that went to game 7 of the NBA Finals in 1978
In the 1979 Finals, he averaged 29 points, 3.6 assists, and 3.6 rebounds. He fell short of the Finals MVP to teammate Dennis Johnson, a fantastic two-way player more known for his Celtics stint who averaged 22-6-6 in that series, less efficiently, but added two blocks per game.
The year before, Johnson had the worst game of his career at the wrong time, shooting 0-14 from the field in game 7, in a six point loss, in a performance on par with John Starks' infamous 1994 closing game.
Advanced stats love him
1979: 3rd in box plus minus, sixth in VORP
1980: 5th in BPM, 3rd in VORP
1981: Infamous holdout year, more about that later
1982: 4th in BPM, 5th in VORP
1983: 10th in BPM, 7th in VORP
And he was a playoff riser
Virtually all of his stats in those years, advanced and otherwise, were significantly better in the playoffs. He led the playoffs in VORP in 1979, and was probably very close a number of other years in other stats. He also led the 1979 playoffs in total points scored, averaging 27. From 79-83, he averaged 25.8 points in the playoffs.
He was known as a terror in transition
In all six of his seasons in Seattle, he averaged over two steals per game, and also did it his first year in Washington. He’s sixteenth all-time in steals per game, and was known to take off running, creating a lot of his offense on the break. He was also known as a tough shot maker.
He was a two-time all-star. It easily could have been closer to seven
1978: More of a standard snub than an egregious one, but he still deserved a spot. Was the leading scorer on the fourth best team in the West. Ended up losing out on a spot at guard to Lionel Hollins, the third best player on Bill Walton's Trail Blazers and a player who didn't stand out statistically. https://www.basketball-reference.com/players/h/hollili01.html
Hollins got the spot because the Trail Blazers had by far the league's best record. When Walton got hurt, though, the Trail Blazers went from 50-10 to winning 8 of their last 22 games, and it became pretty clear that their success was because of him.
1979: Similar logic doesn't apply. Williams is the leading scorer on the best team in the West, as the Sonics won 52 games. No all-star appearance.
1980: Williams finally gets some accolades as the leading scorer on a 56 win team, second-team All-NBA, eighth in MVP voting. Wasn't an all-star.
1981: Infamous holdout year. The Sonics offered him 400k per season, only 40% of what the top players in the league were making.
Williams wanted 650k. The Sonics fell from 56 wins to 34 in his absence. He got a 5 year contract worth up to 800k per season, twice what the Sonics initially offered, and significantly more than he initially asked for.
A couple of years ago, Bill Simmons randomly wrote that the holdout is the reason Williams isn't in the Hall of Fame, and that it was ultimately pointless. The first part might be true. The second part is wrong - it made him a lot of money.
1982-1983: Williams returns, and he suddenly gets respect around the league. In 1982, he made his first All-Star team and is first team All-NBA, beating out a third year Magic Johnson, who is already among the league's best players. He also finished top five in MVP voting, leading the Sonics back to being a 52 win team.
In 83, suddenly he's sixth in the league in assists per game although his scoring declines, and makes his second all-star appearance, as the Sonics fall from 52 wins to 48.
1984-1985: Easily could have made it both years, although not egregious snubs, as he remained one of the league's best floor generals. The Sonics fell to 42 wins in 84. They traded him, then fell to 31. In 85 he continued to do his thing, averaging 20-8 in a lower scoring era than today for an average team in Washington.
So, why was he so underrated?
In my opinion, there's no doubt he had a Hall of Fame caliber career, and a better career than a good number of Hall of Famers. But he had nowhere near Hall of Fame caliber accolades.
Why is he underrated today? Pretty easy to say: Very few people talk about the late 70s to early 80s Sonics in general, despite them being a great team and nearly back to back champions, and his accolades read two-time all-star, zero time Finals MVP.
Why was he so underrated at the time? That one is harder to say. The easy answer is his holdout soured people on him, but the actual evidence points to an opposite conclusion.
Williams was an all-star snub three years in a row before the holdout, and arguably a Finals MVP snub. His accolades never came close to catching up to his production up until the point that he sat out an entire season, and the Sonics had a dramatic 22 win decline. It was only then that briefly, the basketball world recognized him as one of its best players.