Rune sockets for wands and sceptres.

Why are we unable to add them? Why can I not have sockets on my wands and sceptres? The Body and Mind runes are perfect for caster weapons too. Wands always get x% life/mana leech on physical attacks, and even though there are physical spells they don't count as attacks and the meager 10% life leech the blood mage has isn't enough alone and the 26 points to get down to the Merc side of the tree is a huge waste of skill points just to get 5 leeching nodes. Why are there no attack or spell leeching on the skill tree? The few there are, are just increased how much you leech but none offer the affix to leech.