Let's take the "tracking light sources" thing for a moment and pick it apart.
Now, first off, half the party probably doesn't even need a light source - they have darkvision - so, even at first level, the exploration pillar element only applies to half the party.
First, consider that tracking light sources is only a small part of resource management and applies only to some aspects of exploration, so showing how you can solve for light source issues doesn't exactly undermine the exploration pillar. But let's examine it, yes.
If a PC is relying solely on darkvision, that PC has a -5 to PP where sight is a factor, meaning they are more likely to be surprised and run afoul of traps, and would be less likely to spot secret doors if they are searching for them. They also only see in black and white so if there is something important in the environment that color is signifying, that's not great.
Then, we get into mundane light sources. A torch, sure, lasts for 1 hour. You're going to need quite a lot of those. But, by 2nd level you can afford a lantern pretty easily. Now, you have 6 hours of light per pint bottle. 4 bottles a day if you really want to keep that lantern going all the time. Let's say 3. How long is the group actually going to spend in the dungeon? Two days? Three at the absolute outside? I mean, a 2nd level party probably isn't even up to camping in the dungeon if they can avoid it, but, sure, 3 days.
A gallon of oil to power a lantern for three solid days. Not exactly hard to carry.
A torch weighs a pound as does a flask of oil. A lantern weighs as much as two torches or two flasks of oil. The gallon of oil weighs 8 pounds. With the lantern, that's 10 pounds. With the variant encumbrance rule in place - which is what you'd want in a game where an important element is what you can carry into and out of the adventure location - even the Strength 20 fighter is going to feel this weight since it takes up 10% of the weight they can bear before their speed drops by 10 feet. Ten pounds of encumbrance due to that oil and lantern also means you potentially carry out 500 fewer gold pieces - fully 1/3 of the way to plate armor.
Light sources also mean you may be spotted more easily by monsters lurking in the dark. If they have ranged attacks, they can attack you, but you can't see them and thus are effectively blind in attacking back. And perhaps those hateful denizens of the dark
despise the light. A lantern has perhaps 2 to 5 hit points. How about we just go ahead and target that lantern then? You haven't lived till you've seen PCs scramble to protect their lantern!
Now, let's add magic into the mix. Let's see, cantrips: Light, Dancing Lights, Produce Flame, so, every caster save Warlocks can completely bypass the need for tracking light sources.
This was the point made much earlier in the thread. The reason that exploration in D&D is largely ignored is because it is ridiculously easy to bypass. To the point where it can be pretty much assumed that the party will have the means to bypass nearly all the elements of exploration. Need to scout - well, we've got this flying familiar that can UAV all around all day long. Makes getting lost pretty hard. Need to sneak? There are a shopping list of spells that put rogues to shame. So on and so forth.
Indeed, spells can help a lot with these situations. But of course, they come with trade-offs too. Nothing's free.
Light isn't as good as a lantern in terms of range which is why you'll often see the "light rock" deployed, chucked into room and thrown down corridors - not great for sneaking around.
Dancing lights is actually very good in dungeon environments in my view, but it's Concentration.
Produce flame's illumination is even worse than a torch. Plus taking any of these spells means you're leaving some other cantrip on the table. After all, you can only know so many.
Your basic familiar scout is great if you're within 100 feet of it. You're deaf and blind while seeing through it and,if you're sharing what you see with your party, you're arguably not being quiet. And the moment it runs into a monster that can hit it, there's a problem. A simple door will also be a problem for many familiars. Notably a familiar doesn't really have an impact on the ability to navigate (which determines if you get lost) unless the DM says so (perhaps you can't otherwise see the sky without it).
Pass without trace is an awesome spell for the whole party to sneak around, but again, you have to prepare it, it costs a spell slot, it's Concentration, and everyone needs to stay close. (Some disagree on that latter interpretation.) And I've still seen the party fail to sneak past monsters or gain surprise due to poor rolls on the part of low-Dex fighters with heavy armor. There are no guarantees here.
The problem with the 5e DMG is that it in no way actually accounts for this. They talk about setting up "interesting encounters" in the wilderness, (DMG p 106), and talk about setting a "marching order". But, absolutely no advice on how to deal with the mountain of resources that your party very likely has to bypass any challenge you want to set out. Oh, noes, there is a narrow, rickety bridge. One Tenser's Floating Disk Ritual later and poof, we're across the bridge with no problems.
The 5e DMG is written with the idea that the group will never actually use any of the renewable resources it will have available. For some bizarre reason, all the advice seems to be grounded in the assumption that groups will consist of 3 fighters and a rogue.
Tenser's floating disk can't deal with elevation changes. So it will not solve the problem of the narrow, rickety bridge. What it's good for though is piling treasure on it while making your way out of the dungeon - just don't get separated from it or lose your wizard!
So, ultimately, yes, there are many spells and equipment that can help with these challenges; however, they come with trade-offs and it's in the trade-offs where meaningful decisions lay in this kind of game. Should every game deal with this level of resource management? Hell no. I use it for my dungeon crawls and hex crawls. I'm sure as not doing it for my set-piece heavy pulp action Eberron games. But this sort of thing can reinforce the experience of delving into a remote, alien environment filled with hostile creatures that live in the dark and trying to deal with that while balancing how far you can go with what you have and get out alive with something valuable.
But, see, this is the problem.
Inventory resources is one of the easiest things to skip over. Food is no problem. Water is no problem. Light is no problem. Ammunition maybe? But, that's combat pillar, so, not really something we need to worry about here.
What in a typical adventurers inventory can be depleted through exploration that can't easily be replaced by a cantrip or a first level spell?
Again, spells help a lot. Certain class features or background features too. But these come with trade-offs. You're spending preparation/spells known or spell slots on these things rather than on other spells. Fair trade in my view.
Goodberry means one fewer
entangle.
Create water is one fewer
bless.
Light might mean one fewer damage type that would have been super useful against that weird monster on level three.
So yeah, go ahead and take those spells. We'll see how it works out over the next 6 to 8 encounters.
