What enabled the five-minute workday game flaw was your DM allowing you to long rest while cultists work to unleash the forces of hell with no consequences.
This is a bit of a tangent, but I've been toying recently with the notion of metagame time limits. If there is no particular way for the PCs to know when the kidnapped princess is going to be sacrificed offscreen to the dark gods, then from a roleplaying, in-world perspective, any time is as good as any other. But from a metagame standpoint, it's no fun for the players to show up and discover that the princess is dead because the DM rolled a 1 on the 1d20 check to see how many hours they had.
So why not embrace the metagame? Tell the players that, "the sacrifice happens whenever the clock strikes eleven here in the real world." They can still take long rests and short rests and such, but now instead of random encounters being awesome (because free XP!), random encounters are now painful because of the
table time they take to play through.
This aligns the incentives of the players and the PCs: the players are trying to get in as much fun gameplay as possible in the time they and the DM have, and therefore need to minimize the amount of time the players and the DM spend on dealing with random encounters and tabletalk; and the player characters want to rescue the princess while she's still alive, and therefore need to minimize the amount of time the players and the DM spend on dealing with random encounters and tabletalk. (Although the PCs don't actually know that they need this.)
Thus, no more 5MWD.
I don't actually have a problem with 5MWD at my table but I might implement this anyway for certain adventures because I like the clarity of the failure condition and the way it lets the night's adventure be truly episodic.
P.S. What happens if the time limit runs out? Well, once you lose the scenario there's no use spending lots of time playing out the denoument. Assuming you set the time limit to coincide with "whenever we run out gaming time," the DM can simply narrate an ending: "after many more adventures, you cautiously work your way into the main base of the Cthulhu Cult. There you find the mutilated remains of Princess Jasmine. So sad. You take the remains back to her father the king, who cries a lot and asks you whether there was anything you could have done to save her faster. The end, for tonight." Then everybody goes home and tries harder next week.