The Hawks have an incredibly deep bench (whether you like how well certain players play or not), and Woodson /does/ use them.
The problem is that he doesn't use them consistently, or with any rhyme or reason, other than Childress.
For example, in the month of January (10 games):
Tyronn Lue has played 10-15 minutes in 5 games; less than 5 minutes in 2 games; and not at all in 2 games. And 20+ in the Portland game (with AJ suspended).
Acie Law has played 20+ minutes three times (note: NOT during the Portland game), 15-20 three times, and 5-10 minutes twice.
Mario West has played 10-15 minutes twice (3 assists each time, mind you), 1-5 minutes twice, not played twice, and has been in for less than 24 seconds 4 times.
I'd not mention Salim at all, except did you realize that he's had 4 games where he scored double-digit points? Or that in the last game he's played in (the last game in Detroit), he played for 10+ minutes but had only 1 shot attempt?
On the other end of the spectrum, Lo Wright has played 22 minutes once, 12 once, 5-7 three times, 2 minutes once, and sat in 4 games. The 22 minute game: 0/3, 8 Reb (1 Off), 1 Blk, 4 PFs.
Shelden has played 25 minutes once (0/3, 7 Rebs, 1 TO, 1 PF), 11 minutes twice, 4 once, 1 once, and sat in 5 games.
Zaza: sat in 7 games, less than 5 twice, 8 once (coincidently, the game he's being suspended for).
Solo: 18 minutes once (2/6, 7 Rebs, 4 PFs), sat in 6 games (5 before the 18 minute game), 1-5 minutes twice, half a minute once.
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Point in all this: Nobody's being played consistently. Most aren't playing almost every game. And even when they do have a breakout game (Solo), they don't get any measurable reward for it. Instead, they're as likely to DNP/CD the next game as not.
I can understand not playing everyone. Them's the breaks. But the Hawks have a long bench that throughout the season they have used. Just not in the same game.
For comparison, go to
http://sports.yahoo.com/nba/teams/sas/roster and check out the playing times of the bench players for San Antonio. Consistent times. Everyone knows who's playing what, and time can be earned as a reward or taken away as a punishment. Even the guy they picked up in December as a 13th man gets used more regularly and consistently than the Hawks 8th man.