I agree that Reflex saves are great when players are hit by AoE's... maybe better when players make almost all the rolls. However, D&D Next is using saving throws for stupid stuff like "Light of Heaven" and most of a wizard's straight attack spells, when it should be something like 4e's NADs. Having them be interchangable might be a step in the right direction, making who the task falls on be able to be determined by whatever's most convenient - you can have a party make a Will Save to resist sleep, or have the party wizard cast Sleep on a group of goblins and "Roll to beat Passive Will".