As others have said, short-rest based classes aren't supposed to just be on a shorter nova cycle. No class is really supposed to use their limited resources every round. Limited resources are tactically and strategically meaningful. Resource management has always been part of the D&D game, even though the specifics have changed over time.
Now, it is possible to throw off the balance between long and short rest resources, if your group isn't following the 2-s-2-s-2-l (do we have a fancy acronym for this, yet?) pattern. In that case, you have a few options: 1) meta-game so everyone is either all long or all short, 2) DM applies in-game pressure to normalize the pattern, 3) tweak the rules such that the balance fits your group.
Option #1 is really just a decision. If you want long rests and novas, then go with Wizards over Warlocks, Champions (who are more flat balanced) over Battle Masters, etc. If you want short rest balance, then go the other direction. Sometimes, there isn't a good option (no short rest Cleric). In these cases, suck it up and move on. Sorry, this helps with minor issues, but isn't a magic bullet. Of course, it probably fixes the majority of cases, too.
Option #2 is probably the "best" option, but may be the hardest. The balance assumptions are what they are. From a gamist perspective, play by the assumptions of the game and it will work better for you. From a narrative POV, why the heck don't the heroes always head back to camp by noon, anyway? The easiest way of doing this is for the DM to have enemies alerted to the characters' presence make use of those extra 8 hours. If the PCs are harrying the monsters other than the time period the monsters need for their own recuperation, there is less chance of midnight ambushes on the PCs. There's also less chance that the smart monsters will set up a ton of new traps to discourage the PCs.
Option #3 is recommended only for real tinkerers. If it's the idea of stating that you take a short rest that throws you, there's no huge reason why you couldn't go to the 4E model of short-rest resources being "encounter powers" and just reset them after every encounter. I don't think it's ideal, but it wouldn't crash the system. For urban, wilderness, or other non-standard time structures, use one of the variations for rests in the DMG to tweak the resource allocation.
There's other threads for this, so let me just thank you for your post and say my ideal 5E game would have been balanced around roughly half the number of expected encounters per day/longrest.
I would much rather have the game treat a 8 encounter day as an exception than a 2 encounter day.
It simply fits published campaigns much better. As well as my personal DMing style.
It also considerably defangs the "short adventure day" strategy and would have been an overall superior choice.
It would also mean much less work to challenge but not overwhelm my characters. In the (rare) case I have an 8 encounter day, I could simply go easy on the party: encounters rated easy, low-CR monsters.
In contrast, what I'm finding with the current scheme is that most (if not all) encounters that I want to be a game challenge (and not just to serve a story or worldbuilding purpose) needs to be rebuilt, especially at higher levels.
The monsters just don't cut it, since they're meant to be used in long chains whereas I want each individual combat to present a challenge of its own. (Again, not all such combats, but when I talk about a "challenging encounter" I mean one that challenges even a fresh party)
Merely doubling their number is a bit too crude a solution. Instead I find I need to rewrite the monsters, granting them ad-hoc powers.
So my ideal 5E game would have been balanced around 3-4 expected encounters per day instead of 6-8.
You might immediately think I want short rest classes to gain a considerable boost (since each day offers only half as many short rests), but note that is not what I am talking about - I honestly don't have that problem. Despite rarely having 8 encounters a day, our fighter, fighter-ranger, warlock and monk fighters does not seem weak, and we haven't seen them overpowered by our cleric.
Partly this may be because of the emphasis on short resters IMC. But partly because the game seems to offer better paths to minmaxing for martial characters - we're using both multiclassing and feats, and both seems to favor martial (and hence short rest) characters.
Perhaps I need to DM a longrest-heavy party... If four of the five characters were, say, Wizard, Sorcerer, Cleric, and Druid; things might look differently for the lone shortrester.
Not sure though. If anything, I would think the Wiz and Sorq would be very grateful for bringing along a meatshield (while the Cleric and Druid probably could take care of themselves).
