I general I don't feel that basketball sabremetric stats have advanced enough (compared to baseball ones) to be able to isolate a players value well enough to produce an overrated/underrated list based solely on these stats, looking at wp48 in a vacuum. Particularly on the defensive end (defensive efficiency).
First I am not in a position to evaluate the quality of Win Shares as a statistical measurement, other than on an anecdotal basis, and I am sure when I do so I would end up cherry picking the data to make whatever point I want to make.
With regards to this particular article, he compared win shares to PPG scoring, win shares to PER, and win shares to NBA Efficiency. So this is a comparison of Win Shares to these other measurement systems, and the argument he is making is that, for instance, Al Harrington is rated much higher using the other systems than the win shares rates him, not that Al Harrington is overrated per se, but that win shares rates him far lower than PER, or PPG, or EFF rates him.
One thing that clearly stands out to me though is that of the top 20 players
1. Al Harrington
2. Rudy Gay
3. Stephen Jackson
4. Andrea Bargnani
5. Danny Granger
6. David West
7. Mehmet Okur
8. Richard Jefferson
9. Jamal Crawford
10. Jermaine O?Neal
11. Charlie Villanueva
12. Jeff Green
13. Richard Hamilton
14. Thaddeus Young
15. Michael Beasley
16. O.J. Mayo
17. LaMarcus Aldridge
18. Carmelo Anthony
19. Ben Gordon
20. Wilson Chandler
in general these are players who can put up really nice stats, but that production does not lead to lots of wins. Now you can make the argument that West, Okur, Hamilton, and Anthony have been winners, so that means that his argument is wrong, or you can place all of this within it appropriate context.
David West - He is a good solid player, but does he contribute as many wins as PER would suggest, or as many wins as Win Shares would suggest? Pick a team at random, and ask yourself the impact that he would make on that team. If West put up his same stats with Indiana would Indiana greatly improve it's win total? If Chris Paul put up his same stats with Indiana would they greatly improve their win total? In my opnion at least, and I believe that WS would confirm this, Indiana would not see a significant improvement in wins by replacing their existing PF with David West, maybe 1 or 2, but their win total would improve by 15 if they replaced their PG win Chris Paul. The difference in WS between Chris Paul and David West is huge (17.4 to 7.7), but the difference in PER or EFF is much smaller.
When I look at this I see a number of players I have always thought of as being highly overrated, and the kind of players who command big salaries, but don't add to a teams win total significantly. That is the very definition of these players. Their teams consistently under-achieve, they get paid big money, and they distract you with gawdy stats.
Al Harrington
Rudy Gay
Stephen Jackson
Andrea Bargnani
David West
Richard Jefferson
Jamal Crawford
Jermaine O'Neal
Charlie Villanueva
Michael Beasley
O.J. Mayo
Carmelo Anthony
Ben Gordon