Jensen is fast. Other than that, he's nothing special. There's a reason the people who see these players every day on and off the ice choose one player over another.
I think his skating alone makes him special enough to play on the bottom pair. He's got great mobility on the blueline, he can rush the puck up the ice and get back to cover his position quickly. During the TC training camp, he spent some time as Ouellet's partner. While XO roamed, Jensen covered for him. His speed allows him to play a solid two-way game.
I also think he has a solid first pass out of the defensive zone. Ouellet might have better instincts, but I think the way Jensen performed during the preseason is enough reason to keep him up over Ouellet right now. At the very least, he deserves a shot to show what he can do during the regular season in the NHL.