Using a Beguiler for direct damage subdual effects is a bad idea. Beguilers are all about clever tactics. Fighting an archer? Ready an action to cast legion of sentinels when the bow-wielding sap tries to plink someone. At 6th level, you'll probably end up inflicting 8d8+8 damage from the ensuing AoO.

A few levels later, you get winners such as confusion and incite riot. Cast these back-to-back and your enemies will shred each other for you. Rainbow pattern followed by a long walk off a short pier -- or maybe a long cliff is another great tactic.