Later in the game Explosive Arrows are not the best choice for attacking single targets, and even for groups you'd still probably want decent damage on your standard attack (waiting for cooldown times or mana regeneration).

You still have plenty of freedom on how you wish to distribute your stat points, though.
I described my ranger playthrough (with lots of spoilers) in the topic Who's playing DKS on nightmare difficulty ?. From my (currently) second last post in the topic, I quoted my stats and skills on level 37 (I stopped distributing stat points on level 15):

At the end of the Hall of Echoes, I had 98 unused stat points, and 21 unused skill points.


Code
equipment            with  without

hit points           942     306
mana                 639     222

Code
vitality              53      14
spirit                22       2
strength              21      21
dexterity             51      36
intelligence           7       7

Code
damage              281-425
magic damage        114-133
melee resistance      22.1    10.4
ranged resistance     38.5    16.6
magic resistance      37.2     3.7

conditioned body      21      21
heightened reflexes   74      36
indomitable will       7       7


Skills

Ranger Strength - 10
Explosive Arrows - 6+8
Splitting Arrows - 7+3 : these 3 I should probably max soon

Poison Arrows - 1
Stun Arrows - 1 : secondary skills

Death Blow - 1
Evade - 1
Healing - 1
Regenerate - 1 : tertiary skills

Lockpick - 5
Ranger Stealth - 5
Mana Efficiency - 6
Mindread - 15 (1 up until shortly before entering the Hall of Echoes)


Before the battle tower I had a couple points in Poison and Stun Arrows, as well as equipment bonuses (recently replaced some +2 Poison Arrows earrings). Both still come in handy, but mostly just as a way to pause and select a specific target, then come out of pause attacking (a normal ranged attack doesn't unpause the game).

I'll probably boost Death Blow when I have lots of skill points I don't know what to do with, and after that possibly Regenerate, then Healing.
Lockpick will get maxed when I can raise the level cap. Unless I start upgrading to equipment without mana bonuses, I will not need to invest any more into Mana Efficiency.


For testing skills, it would be better (and cheaper) to save before learning them, and then simply reload to go through the same group or fight the same tough opponent repeatedly. Resetting your skills costs gold, and the price doubles each time you do so.