The Mavericks don't seem to have a problem with soft bigs...
I'm not sure if you are being ironic. The Mavs are all but precluded from playing "small ball" because Dirk is such a terrible defender. Without having big rebounder shot blockers at center, their defense is really awful.
Except Gasol is Option #1 on his team, big difference.
Gasol is a first rate offensive player and a good rebounder, but like Dirk not physical enough to defend the post. When playing with small but athletic guys at PF, their defense was just awful. Last season, opponents shot 48.6% and outscored the Griz by -5.1 ppg.