But that ISN'T the 15 minute workday- your party got clocked and couldn't do much of anything until they recovered significantly. They were inactive because they had suffered a major setback; they had little choice.
The point was to point out the effects of being underpowered. Given how M&M works, there's no issues with 15 minute workdays in it.
IMHO, that's a pretty significant reason. Restraint in spellcasting has usually served me and my fellow table-buddies pretty well over the years. The sight of mages doing coup de graces with daggers or firing crossbows at peripheral targets is pretty commonplace in the campaigns in which I've participated, and it let's them conserve their REAL power until it's needed.
As I mentioned earlier (I think on the previous page), getting your head around 3.x resource management is
not easy. There's no guidelines for knowing how many spells to dish out per combat, and often players want to cast an attack spell every round. It doesn't help that your best attack spells are your top-line spells (save DC issues, if nothing else), and you rarely have time to use more than one defense/buff spell* (not counting buff-n-scry situations, of course), which means few rounds spent on the lower-level defensive spells.
*(Except the occasional inexperienced player. I can never forget this new player, playing a mid-level cleric [joined the campaign late] wasting three rounds on buff spells. By the time his initiative rolled around for the 4th round, the battle was already over.)
IME, even if DMs use lots of time pressure, the PCs still dish out spells until they're tapped out of high-level slots, and then realistically have to stop adventuring.
Mind you, I have seen lots of wizards do the CdG thing, but only in 2e. Spell selection was much more limited, and you had fewer spells per day. (Also, darts didn't sucks, not when you can throw 3/round.)
It's not MAGICAL, but so what? It IS good tactics...a something a very intelligent (Wizards) or wise (divine classed) persons would grasp.
Good tactics, crossing with player fun. Maybe part of the problem is that "novas are fun" or "disintegrate is more fun than using a crossbow".
While a lot of visitors here seem to dislike the lack of Vancian magic in 4e, I'm glad it's (almost) gone. A magical PC can do something magical every round, and you get one or more encounter powers to play with, so barring being surprised by magically disguised elves, you should always have those available. Even if you've used all your dailies, you're not hosed if you're tapped out of them, so PCs are more willing to press forward and not huddle in a hole. (If anything, IME, PCs rarely use their dailies in 4e, hoping to "save them" for when something nasty happens. Same with action points.)