Reposting my thoughts from a thread on Monte's boards.
The party stops, despite having wands, potions and other non-spell-dependant resources because their
flexibility*
decreases as the higher level slots of spells exhaust. Enemies are scaled based (in part) upon the assumption that PCs have their highest level slots available.
3.5 took away certain "all day" buffs in an attempt to "solve" what wasn't a problem. The perceived problem wasn't the caster. It was the target of the spell, which was not "personal". (If it were only Personal, that would lead to separate sets of arguments that "Wizards get to do more! Wah!" of course.

) Monte's suggestion of "all day powers" ties into that.
D&D design could have, but did not, head down far down a path toward what I call the Championizing of D&D.
Champions is a superhero RPG where you designed all your powers "off the rack". D&D is getting closer to that with all the options. You want to be able to deal hand to hand damage? Buy this feat and that weapon. In Champions, it's covered with buying it as a power with a focus, or a skill. Different methodology, but ultimately the same idea. Take X effect, add Y modifier, and get Power Z. Ironically, AE moved a little close to this with spell templates and weapon templates and so forth.
Extension of play (or not stopping when the party is out of spell slots) has loomed larger in 3rd Edition because there are more options for players. I somewhat disagree with the following statement:
previous editions' ways trained players of spellcasting characters
Because I don't think it was just spellcasting characters who had to think a lot more about their environment and how to use it effectively. Over the past three years of running a lot of convention games, I've seen the occasional First Edition player who comes up. They invariably look at the
locale of the adventure before thinking about
abilities upon their sheet. (Sometimes when they look they go "Oh wow, cool!" though.) They think in terms of clever uses of mundane items and normal terrain. This is not to say that the typical 3rd Edition player doesn't do that. They do. But they tend toward looking at a) what their abilities are, b) what other PCs abilities are and c) what other magics the party might have before trying a "mundane" solution to an unusual problem. Unusual problems don't crop up every encounter though, so I ultimately think 3E made some very right decisions for better play.
To address one point in the article:
No longer does a spell like fireball need to be regulated in the same way that a spell like confusion does.
Fireball however has area. The one reason that wizards are so highly prized over archers is area. You can toss a 10d6 smackdown on a large crowd, clearing out quite a few opponents, or softening them up for a couple blows or arrows from the rest of the party to take out. Certain high level games demonstrate that fighters can also start to duplicate this feat. Having Cleave, Great Cleave and some Complete abilities and dealing out hundreds of points of damage in a single round, for example.
One notion that would be fun to toy with is the idea that certain abilities like adding
area, greater
range, or other form of increased
effect are powers. (Getting back to the
Champions analogy above.) That would tie into Monte's idea. You could choose a daily "power", like
Modify Spell, for example.
All of that said, the idea has a lot of merit. It would be very cool to see something developed from it! I think the system Monte is proposing might actually fly better if it were not constructed specifically for D&D. I'd like to see it as a D20 game, or something further afield.
*Flexibility is akin to movement. Both are highly desirable abilities in 3.5 because they let you cross greater distances, ie access more options. If you have a fifth level caster who can cast third level spells, think of it in terms of having "Move 30". Isn't that more desirable than being stuck at Move 20? At move 20, or worse, 10, you have a very limited number of squares. Tactically, you are much more of a sitting duck.