Its called resource management, and its a part of any conflict. The archer with 20 arrows makes the same kind of decisions.
We're back to dueling anecdotes, then, because in all my years of gaming, through every edition, I think I only ever met
one DM who actually made the PCs count ammunition.
Which, BTW, is why he also makes sure his PC upgrades his weapons from time to time, just like the warriors and rogues. No 6th level spells? No problem- eat bolts from his Brilliant Energy Crossbow!
Of course, he wasn't going to
hit that often with it...
As I read 4Ed- indeed, as I believe you yourself posted earlier in this thread- this kind of resource management has not disappeared, its just shifted to a different mechanical part of the game.
Well, yeah. I'm not arguing for the elimination of resource management.
Feel free not to delve- but I'll say this anyway: our parties tend to go 5+ combats between rests, and my buddy's Wizard will usually still have spells to burn at the end of that stretch.
Fair enough. Now consider two aspects of the reverse.
How many other resources did the party burn--ammunition (if you're counting that), healing spells, hit points, disposable magic items or charges, or other types of damage like ability drain--because your buddy didn't hurl some of those spells earlier?
And in how many rounds of combat did he accomplish nothing of note,
other to save those spells for later--when they arguably didn't do him any good?
I think that's a definition of "effective" that could be argued. On the one hand, it's always nice to have a reserve. On the other, any spell wizards in prior editions had left at the end of the day was something they
could have accomplished in combat, and didn't.
This is a game that needs to appeal to a wide base of players. Some people enjoy the resource management more than other stuff, sure. But I'm willing to all but guarantee you that your
average player, standing around for several rounds and not casting spells just so he might have something to fall back on later, is going to feel like he's not getting to play his wizard to full effectiveness.
So again, I say a class build that lets you
choose is better than one than
forces a level of caution or hoarding of resources so intense that you wind up doing nothing--or resorting to your crossbow

--for a significant portion of combat.
As far as resource management... The difference is that, using healing surges and daily powers, you're still at high effectiveness until you're completely out. Dailies are cool, but you can forge ahead without them. Healing surges are vital, but you don't fight more poorly without them.
In prior editions, a wizard's resource management also mandated his ability to
do anything. If he's out of expendable resources, he's out of
spells. He's reduced to an archer with a crappy BAB.
As I said, I'm not arguing for the removal of resource management. I'm just suggesting that a system where running
low isn't the same as being almost helpless might be reasonably said to have a broader appeal, and contribute to people feeling more effective/productive more of the time.