[Sponge]

I'm currently level 15 using a Screaming Mace, and Unicorn Shield.

If you want to increase your aggro generated, never ever use a shield, instead use two one hand weapons that proc some sort of stun/dd/snare/whatever on your target. Having high dex helps too.

I'm lucky if my taunt does anything at all

Taunt, if successful, puts you at the top of the aggro list ahead of the second person by 1 aggro point. Once you are on top of the list, the only way in classic to keep building aggro is to continue to do damage, procs, and other abilities like kick/disarm/whatever (if disarm wasn't broken...). Taunt does almost nothing if you're already at the top of the aggro list, it is not a good way to build aggro. Try and save it to use immediately when you lose aggro. It also fails.. a lot.. and in classic there are no failure messages.

Taunt isn't very useful until higher levels when you are fighting blues.

This doesn't really make any sense, taunt fails more on higher cons, but it still works...

Warriors cant old aggro over SK // Pally's due to super-hate from spells.

Any Pally/Sk in a group as dps with a warrior that is tanking should learn to minimize their hate by not casting stuns or snares, etc. However, in an all out competition, I'm sure a hybrid would prevail.