I really think it was a mistake to retain the short rest mechanic from 4E. The older editions functioned so much better without it.
It was changed quite a bit from 4e, which, like 1e, assumed the party would rest for a bit (bind wounds &c) after most every fight (3e also had a sort of short rest, thanks to the impact of Wands of low-level spells like CLW or Lesser Vigor, you could heal everyone up in a few minutes after every fight for a fairly trivial cost in consumables). 5e's 'short' rest is a full hour (to overnight if you use the 'gritty' variant) so you can easily have two or more encounters between short rests. 3.x/PF and earlier, most classes were either all-in on at-will or all-in on daily, with hybrids, like half-casters or multi-class fighter/magic-users & the like, splitting the difference, and coming with issues of their own.
In 4e, along with the class designs investing less overall effectiveness in daily resources, it meant the number of encounters/day mainly affected relative encounter difficulty: the party could be taxed to the breaking point over a very long day until even a level-1 encounter would look dicey, or it could engineer a single-encounter day and pull out all the stops taking on a more brutal encounter than usual with a much better chance of success. But, class balance didn't vary wildly with the day length the way it did in other eds, and does in 5e. So you could run a campaign that tended towards single encounter days, consistently, or one that varied around an average, or one that tended to long, grueling days - all with minimal issues.
And, for the first time, 5e has classes with a very significant portion of their effectiveness wrapped up in short-rest resources (the Warlock probably the prime example). Balancing 5e via pacing is thus as or more complex an exercise than it's ever been, with how you do it depending on party makeup, among other things.
And it was interesting.
I'll post the encounters below, but the short of it was that a thief (technically speaking, a warlock) stole an altar with a *god* in it (a very minor one, but still) and fled into a dangerous jungle. The party had to give chase before the tail grew cold or the warlock did something dangerous with the god.
The party (All level 7):
Monk (open hand)
Monk (drunken master)
Warlock (tome/topaz dragon, missed session 2)
Paladin (order of the ancient)
Cleric (knowledge, missed session 3).
So three short-rest types, and the two long-rest types (both healers) have more solid baselines than the stereotypical D&D magic-user... if they get the odd short rest, should be able to handle 6-8 encounters, no problem. If it gets rough and there are multiple short rests to burn HD, and the divine magic goes mostly to healing, it could be a frustrating day for the Cleric...
This took about 3 sessions (of 3 hours each) to do. The party had a single rest during the adventure (plus one at the end). And... it seems to really had an impact on the "long rest" classes, esp the paladin, who was out of spells, out of lay of hands and had 15 hp rest after the big fight. He complained that this really advantaged the short rest classes, but I pointed out that the reverse advantaged *him* so...
Actually, sounds rough for the short-rest types, too, only one short rest where 2 or 3 might be expected.
So yes, 6-8 encounters/day DOES help with class balance. But even after doing this, I can't help but note that this narrative structure does not work for all adventures...
Of course.
This fight should have been a *joke* for the party (the chieftain was a reskinned veteran with 15 AC and 70 hp, there was a 40 hp shaman (a druid-ish character who managed entangle, fairy fire and feign death) and 6 tribes-chickenmen (reskinned thugs who also had javelins). But it was actually fairly difficult due to low resources.
See? Working as intended! Not 'too easy,' afterall.
BTW: I like how you didn't limit yourself to actual fights when counting up 'encounters.'
Well done.