Run divination spells as plot-fiat rather than a mechanically reliable source of information.
Make challenges situational rather locale-based.
Insist that players make characters with a place in the world and priorities, rather than being rootless violent hobos with no homes, loved ones to protect, or causes to serve.
Remember the Rule of Fools. What one fool can do, another can, too. Societies and rulers, as well as villains and wealthy NPCs, will have their own high level casters and powerful magic items at their disposal. If thieves have magic, then merchants will have magical defenses. NPCs will act rather than sit about waiting for PCs to act upon them. No spell or class features will be available to PCs only.
Fight dirty.