I also think what this says is that we need players who are well rounded and versatile in order to be effective. Foye is a good shooter, but he's average at best on defense and he doesn't rebound much. Marvin Williams is a mediocre shooter, decent defender, and below-average rebounder. Tinsley is a decent playmaker, but not a skilled shooter, and also a fairly weak on-the-ball defender. Millsap has been limited offensively and struggles to guard longer PFs. Jefferson is slow out on the floor and isn't the most disciplined rebounder. This creates gaps out on the floor, basically seams, where players are only effective in limited areas or situations and they can be exploited elsewhere.
Every player in our starting rotation has weaknesses that hurt the team. But I don't think we can be that harsh on Jefferson and Millsap. ANY PF/C combination that plays with Tinsley, Marvin and Foye is going to lose ground.
If you look at our best-performing lineups from last year, they were led by Jefferson and Favors. The difference is that last year those guys were playing with Devin Harris, Gordon Hayward and either Paul Millsap or DeMarre Carroll. This year our backcourt has been a mess.