I've beaten the game as an archer.
Bow expertise--yes
Augment Defense--no
Elven Sight--don't need
True shot (Heard this was broken, is that true?)--yes it is true
Enchant Weapon--helpful
1 point in Repair--definitely
Splitting Arrows--yes
Poisoned Arrows--no, get poisoned weapon, the survivor skill
Spiritual Arrows--no
Elemental Arrows--no
Explosive Arrows--ok for fun
Splitting arrows and poisoned weapon are an incredibly good combo which will kill any monster including Josephine.
Check out this thread.
Archery as a warrior