With my warrior in the original release of D2:ED, I put 2 or 3 skill points in Rush Attack early in the game. After getting the battle tower (in the late teens or early twenties for character level) and unlearning all my skills, I only put 1 skill point back in.
If you are going to do a significant amount of melee combat, then you should upgrade the duel wield expertise. If that is more of a backup, though, you don't need to worry about it, since the off-hand penalty is not taken into account for the magic damage bonus/enchantment that gets added to spells from your weapons.