I used the EDITOR to give one of my characters a 40 luck from day one and he:
1. Doesn't get hit that often, even though he has an armor rating of 24 %
2. Almost never gets poisoned when bitten by spiders, chitrachs, or other nasties.
3. Hits almost all the time, even with low points in a given attach style.
I have no idea how Luck factors into the math of the game, but a high luck really did help.