The game doesn't really let you dump stats. 8 is only just below average and a -1. Which I appreciate, I think it gets a bit silly if you can dump down to 3 or 4.
I actually find Strength the easiest to dump and most fitting for most characters. Unless you are playing a strength based fighter type, its not necessary. Sure extra jumping and carry capacity is handy but not essential (but this is why if I have one odd point left I usually put it in Strength).
And while Constitution is always good . . . given how much healing is in the game (food, potions, etc) . . . you don't need as much as you would normally.
