Rend is better than mana missle later on in skill but yea, pretty useless all in all. Mostly good for getting from 0-50 greater with bone while working your Riger and Con by hitting yourself.

Spells aren't all uselss. Launch is awesome for getting random places, unencumber lets you wear up to banded with zero armor penalty to magic. MM is free and good for PvE and PvP if it's leveled. All of the lesser magic transfer spells are good (heal self, mana to stam, stam to health and health to mana).

If you want to be a mage, you need to pick up all the little extra crap from the schools (durable, intesity etc) then pick up the buffs for having over 300 mana etc etc. All of these raise your int faster, giving you more dammage. You also don't get any benifts of higher level spells with low rank staffs. Come back when people are at 100 int, 100 firebolt with a rank 80+ staff and see how a firebolt to the ass feels.