The problem with the 15-minute workday is not that it happens all that much, but that it causes the DM (unnecessary) work to prevent it from happening, and in some cases causes the players to have incentives that are perverse compared to what they want to do. I see this most often in my group when you see this kind of statement, "There's really no mechanical reason why we should press on, but I guess we are big heroes that would do so." In other words, if I don't work to make sure that they always have a reason, then the disconnect takes them out of the game world.
There are no mechanics that can totally stop this, it's true. That's a damn poor reason for not experimenting with some mechanics to work on it around the edges. "Hey, the dishes are going to get dirty anyway. What do you need a dishwasher for?" There
is a middle ground between going out for every meal versus eating on paper plates all the time--or being a purist and washing every dish by hand.
Moreover, a certain slice of the problem is not caused by Vancian magic alone, but by the intersection of Vancian magic with hit points. No one is really all that upset if the party wants to rest when the spells are gone and the hit points are approaching single digits. That kind of
pacing is exactly what Mearls is talking about contriving in the article.
One of the tools I'd like to see is an option that recognized that the hit points are the prime pacing tools, and worked accordingly. Namely, disallow recharging of Vancian spells and other such powerful resources for free (except maybe between adventures in restful, secure locations over several weeks*), but
do allow them to be recharged with hit points.
That effectively means that the party runs out of resources when they run out of hit points. Now, you don't need to contrive anything, because it always works out that whether you are getting smacked or casting spells or whatever, when you hit that point where the hit points are low, the party is going to want to rest.
Naturally, you'd need to watch the healing magic, especially items. But that's a nice feature, too, in that if the party is in over their heads or doing really well, finding or not finding a few extra healing potions affects the pacing the way you'd expect. It should cost enough in hit points to make recharging a cure light wounds a bad idea. You might charge a premium for such spells to make recharging other spells more atractive.
Finally, this might have a pleasant side effect on the "clerics as healbot" issue, albeit only on long adventures. It becomes highly attractive for the cleric to start an adventure with mainly cures, as these are hard to replace. But then when used, the cleric does replace them with other spells--which now the cleric is highly encouraged to use as needed.
* If you make the recharge of Vancian spells always take hit points, then you can get some interesting opertional and strategic decisions when the party is in a secure location, but unsure of how much time they have before something big happens again. If you like this kind of thing, it would be good to not allow free recharge, and let the hit points the party is willing to risk be the guide. It becomes a more interesting mechanic than flat time for recharge, and also really makes natural healing interesting. However, if this part doesn't appeal to you, then such recharging at rest becomes a bunch of accounting, and you'd be better off to allow straight regain at rest on the grounds of fast play. In either case, how you handle that isn't crucial to the rest of the idea.