I think Phaneuf is not the elite defender to anchor the group unfortunately. He is not a Weber/Chara/Doughty/Keith caliber defender. Having said that, his contract term and salary make him hard to trade.
So, in all likelihood, the Leafs will have Phaneuf on their blue line in the top pairing and need to find another dman that can be a steady #2 guy to bolster the top pair. In time, this will likely be Reilly, but its probably a stretch to think he will fulfill this role next season.
Unfortunately, such defenders are in high demand and limited supply in the NHL. I see our blue line as being a weakness for a couple of more years unfortunately unless Nonis can pull a rabbit out of his hat or something.
Further down the road, the Leafs have some prospects in their system that should be able to make the jump to the big league. Maybe one player (Granberg) makes the jump next year, maybe not. I think we are couple of years away before we see any kind of larger impact from the infusion of these prospect defenders.