UConn won a national title playing only six; Washington went to the Final Four last year playing six.
Very few teams at any level play more than seven or eight players in big games for any extended amount of time. There's just not enough depth to make playing nine or 10 in the rotation a viable option.
The Warriors are the exception that proves the rule: They have an incredibly deep roster which is one of the big reasons they set an all-time record. If you look at the other teams in the NBA playoffs, the dropoff is pretty steep after the first seven, and in fact many of them really don't have five quality starters (looking at you, Mason Plumlee).
Clay,
I don't think it is
depth so much as it is
productivity and playing to win. Most players aside from Curry, Durant, Ray Allen, and Klay Thompson must get into the
flow of the game to hit their stride. So good coaches know you must
let players get into the flow of the game and leave them out there. I see why Uconn keeps winning. You substitute very little. Just for a brief rest or foul trouble in
closely contested games. Play (5-8), Seven to eight players is most likely best. It's the CYO mentality coaches (and parents) that believe you have to be fair. I say be fair to the team by putting the most capable starters and subs on the floor. The
game should dictate who plays not the coach IMO. If a starter or two are just not there that day they too should be shown the bench to see if someone can give the team a
spark. You always put the
team's progress before any individual player(s). But you do need to develop your bench and role players too for the post season or years to come. That should be done when the teams and games are not quite as challenging as post season or championship caliber games. Or when you have put the game a bit out of reach. There are some teams that have quality backup players, this season's St. Mary's of Stockton was an example. But even they must
limit the rotation in
some games. Rotating
too often never allows the team to get in sink or gain any momentum. Limiting the rotation allows players to get into the flow of the game, and allows the team to get a run going. You also must take into account how well your team(and each player) is conditioned, and the
tempo of the game. Also different combinations work in different games depending on match ups. You may have a big heavy weight bruiser or a 3 point shooting ace you call upon in certain situations. Again the
game and
each circumstance dictates. At least that is how I see it.