I mostly GM (haven't run DnD 3.x in a while, though) and I love the idea. Trying to make spellcasters run out of spells at high levels was a pain, and trying to keep PC spellcasters from sucking at low levels was also a pain.
I think the change frees GMs to use harder, more interesting and exciting encounters instead of wimpy "attrition-based" encounters. The "resource management" would be threat of death rather than trying to make spellcasters consume spells and wands.