I think the fact that both Smith (signed through FA) and Jennings (signed and traded) both chose their destination is a positive for Detroit, especially considering they are both on less money than they initially desired. Both players have made it known for a long time now that they wanted a change of scenery and ending up in Detroit, a place they've chosen themselves, will hopefully turn around their on court performances as well.
The second positive about their deals is that should things turn pear-shaped and either/both start to carry on, their deals are much more tradeable now that the Pistons haven't overpaid them (especially Jennings). Regardless of how the team clicks, Detroit now have two talented pieces that they didn't have before.
As previously stated, Chauncey Billups role in the locker room is going to be huge. The influence he could have on Jennings could shape the young lads career. He also provides Coach Cheeks with the option of disciplining Jennings when he's forcing up bad shots by playing Billups and without losing too much on the floor. He'll still have his work cut out but I think the Pistons have taken some considerable leaps forward this off-season.