Getting rid of good players and keeping crappy one is not a "system."
Look, Booker was an exciting player, but he was ultimately a third string running back who couldn't block and couldn't play special teams. That's why he got traded, despite his talent and elusiveness. He was a fan favorite, and I wish him well in Philly, but trading him for a 4th round pick was a reasonable move. And Shawn Murphy, picked in round 4, has a lot more of chance to positively impact the team (which desperately needs another starter at guard), though time will ultimately tell.
And back to the main point here, which is Paul Soliai better get off his ass and demonstrate his ability, or he's gone.