I guess that depends on how you play. I spread mine out between those 3 attributes because... More vitality makes you harder to kill. More piety means you can sing longer ^^. And yeah last but not least dexterity makes you hit harder..
Only all your gear on the left side and most of the accessories already have dexterity.
It's ultimately up to you. If you don't like it.. Buy a hymnal tome from the grand company and reset those points into something you need more.