Here's my thoughts: It is harder to find a player like Ewing than it is to find a player like Chandler. Not only was Ewing a great defender and rebounder, but he also was a go-to scorer who could hit contested shots. He was also a very good foul shooter.
But it is also very difficult to find a player like Chandler. He's a true 7 footer that rebounds, defends, can finish around the basket, and doesn't take shots he can't make at a high percentage.
So let's divide skills into two sets:
1. The ability to defend, rebound, and take only shots you can make efficiently,
2. The ability to be a go-to scorer and hit contested shots.
Here's the thing: according to the conventional wisdom of what makes a player a 'star', skillset 2 is much more important. But what Win Shares is so good at is reminding us that skillset 1 is equally, if not more important. I think we can all agree that people with both skillsets 1 and 2, like Ewing, are truly elite players. Often, players with only skillset 2 are considered by many fans and pundits to be stars. However, people with only skillset 1 are almost never considered stars.
That's what Win Shares and Wins Produced counters. It's not perfect, but it debunks the idea that people who can hit contested shots, but do so not very efficiently, and don't get rebounds or steals or assists are 'stars'. And it makes stars of people that have skillset 1 but not skillset 2. And it backs that up by relating those skills to actual wins.
Just as an exercise, imagine that you split Ewing into his skillset 1 part and his skillset 2 part. His skillset 1 part would look a lot like Tyson Chandler. His skillset 2 part would look a lot like Eddy Curry. Or, to me more charitable, Brook Lopez. Which guy do you think will win you more games?
In conclusion, Tyson doesn't have everything Ewing had, but he has all the really important stuff.