Is there really a 'strongest class' in 5E?
Possibly not in the absolute sense you seem to be implying. It hasn't been broadly acknowledged, and probably can't be said for sure until the end of the run, but 5e probably shakes out into Tiers much like 3.5 did at the end. Full neo-Vancian casters (and perhaps even the Bard) in Tier 1, other full casters in Tier 2, and so on. A big difference is that no class is intentionally PC-inadequate (like the 3e Commoner) as to require a Tier 6, nor, arguably, quite so badly botched as to fall into Tier 5.
My complaint is that there are vocal supporters on this forum that absolutely refuse to see problems with the breezy "just use the 6-8 encounter day" universal solvent.
That's not real advice. That's more like "to make the game work, just spend hours and hours fixing what WotC didn't do right in the first place" What I can do about it? Not much. Other than refusing to just take that "advice" lying down.
If you don't want to put a lot of thought or effort or 'DM force' into making the game into what you want, you can 'just' run it straight, and that is, assuming a fairly diverse party and not wanting to have to worry about imposing balance any more than absolutely necessary, indeed, the 6-8 encounter, 2-3 short-rest "Day." Probably in a directive ('railroad'), tailored-challenge style. Because it's comparatively easy on the DM. You plug in numbers, set up your encounters in a line, and let the players chew through it. Even that takes some work, but if you want more from the game, you need to put more into it.
The other way to run 5e relatively care-free, or at least prep-free, is not to bother with encounter guidelines or much of anything else, and just spin the descriptions of the world out as the players explore it, and rule on each action as it comes, even down to actual combat. It's two steps away from freestyle RP, but it can work if it fits your style, and only requires effort from the DM at the table, no prep. Maybe that's unrealistic for most DMs, I just mention it because I've done it a lot over the years, and in systems much less well-suited to it (which really makes me appreciate 5e).
But prior to 3e I never had a big problem with 5 minute adventuring days, fighter/wizard class imbalance, and suchlike.
You're not a lone, a lot of folks never had a problem with it. In either sense.
Wandering monsters were one big reason.
They could put some pressure on the party. Back in the day, it seems like there were always plenty of assumptions/fears that justified clearing as much as possible before retreating from the dungeon. Traps could re-set, intelligent monsters could recruit re-enforcements, repair/strengthen defenses, hide or move their treasure, etc, new monsters could wander in, access to sections of the dungeon could collapse, rival adventurers could step in and clean the place while you were gone. I'm sure I'm forgetting a few things. Heck, even the first/longest 3e campaign I was in (full run, from 3.0 release to after 4e had hit the shelves, 1st-14th) tended towards some of those factors, especially with the dungeon/treasure-hunting scenarios. There was even a rival adventuring party, made up of the 3e iconics, that we'd sometimes be racing against, the rivalry between Tordek and our Dwarven Cleric, Schralk was particularly pronounced (they were from rival clans or something).
I did see it in C&C adventures converted over from 3e though. The issue seems to be around 3e-style linear-series-of-encounters adventure design, where the PCs know they can retreat & rest.
5e is a bit of a hybrid of the earlier editions, it seems to encourage 5MAD more than 1e-2e or 4e, but less than 3e.
That fair, as far as perceived player incentives are concerned. You get a lot, mechanically, for resting, and nothing for pressing on (those incentives all have to come from the story elements or environment or situation, no action-points or item-dailies from milestones or anything like that). I suppose there could be a house rule that facing a second or subsequent encounter without a rest in between earns inspiration (we bad!), but that'd undercut the RP-carrot point of inspiration (hmm, since I'm not much for DM-moderated RP incentives, I just might do that).
I am strongly tempted to do this, but with a cap at 3 short rests/day. That should keep
the SR PCs balanced with the long-resters with typical 3-4 encounters per day of dungeoncrawling.
Edit: I've just proposed 15 minute short rests to my group.
I suppose a compromise between shorter short-rests and hour-long short rests might be to have short rests be automatic after each encounter, or relatively short (minutes) but require at least an hour between short rests...?
If I want to run a sandbox or hexcrawl, where is the support from the game itself rather than a reliance on me knowing what I'm doing? Compare the DMG to Kevin Crawford's stuff. That has good support in both advice and tools for running a sandbox. The DMG has nothing. What if I want to run an episodic game? You're telling me that I'm doing it wrong and I should run a sandbox.
Doesn't the DMG have DMing advice, a selection of 'modules,' and the like? (I haven't actually read a DMG cover-to-cover looking for DM advice since 1e, they're just reference books to me, these days, and not heavily used ones.)
I'm just not seeing the GM tools, quality of life support or much else for any model of running the game. Ultimately I feel like with 5e if you don't already know what you're doing, you're SOL re: DM tools and supports.
A number of 5e's goals - being D&D for everyone who's ever loved D&D, re-uniting the fan-base, supporting more varied play styles, evoking classic feel, DM Empowerment - all point to the target audience being relatively experienced players & DMs. Particularly DMs. If not experienced, at least enthusiastic to be coming back to D&D.
Most common: Low level character gets knocked to low HP, then eats a next max damage hit (or a crit) and and dies.
I've seen plenty of those, at 1st level. Of course, I run 1st level a lot, since I run intro games at cons and the odd launch event, more than I run whole seasons.
Second most common (and all other deaths!): Player gets dropped early by a high alpha monster, rolls a 1 on a death save and dies.
Edit: Also, for various reasons the groups I've played in have been bereft of clerics so the low level ranged healing spells haven't been common, but I bet I'd have seen about 30-40% less deaths with them. But we're not forcing people to have a particular spell for game balance... right?
In-combat healing is critical to get allies up and back into the fight, hopefully with enough hps that they won't be one-shot-killed. Even in just the Standard game, without feats, it's easy enough to come by: 4 or 5 classes have healing spells on their lists, and there's a cantrip that auto-stabilizes, and medicine rolls to stabilize aren't exactly difficult, even untrained. Unless you're running an unusual 'godless' campaign that lacks Clerics/Druids/Paladins, it seems unlikely you'd ever have no useful in-combat healing (you'd have to have be using no casters, at all, and not using feats, and restricting access to even common items like potions, for it to be really unavoidable).