Wands are supposed to be weak. If you want more power, make a rod. You can gain the craft epic rod feat. Rods are underutilized in D&D while wands tend to be over-utilized.
Wands may be weak, but it's logical to assume that someone at the power of Elminster or Mordenkainen (ie, epic level) has figured out a way to make wands more powerful than they are, if only to avoid having to prepare those situationally useful spells.
Also, Deities and Demigods wasn't made using the ELH rules, and due to that, most of the deities in that book could probably be taken down with a well optimized Lv 30.