C/4

Control Water

The effects of this one, particularly the flood aspect, are so sensational that you can almost lose sight of the fact that it doesn't have a lot of practical applications unless you hire yourself out to the city to do civil engineering on the cheap. Admittedly, if you're looking for a distraction or a way to cause mass havoc, causing an entire city to face post-polar-icecap levels of water damage, or crashing a huge wave into the middle of downtown, are pretty good. The main problem is that you face all those same circumstances, so unless you put together a bunch of peripheral spells (Breathe Water, Swim, etc.) or a Contingency or three*, you're literally going to be in the same boat as your enemies. Still, a real doozy for a 4th-level number.

Real-World Rating 5 (Effective But Limited)

Control Weather

Rather the opposite of Control Water, Control Weather is a high (8th) level spell that sounds amazing, but in fact is much less effective than it seems. For one thing, it's a Concentration spell, meaning you basically can't do anything else while it's in effect. Second, it takes forever to work: ten minutes of casting time, plus another eleven to fourteen minutes to take effect. Too long! The weather will change by itself in that period!

But here's the real turd in the punchbowl: the spell presents you with three weather conditions (Precipitation, Temperature, and Wind) with six levels each, and only allows you to change it by one level, up or down! This is worthless! You can't do something actually useful, like change a clear day to one with driving hail. All you can do is change, say, slightly warm weather to slightly cool weather. What can you do with that? Even at the extremes (say, changing a hot day to an extremely hot day, or a gale into a storm), you're just ramping up something people are already experiencing. What good does it do to make normal weather a different kind of normal, or to make terrible weather slightly worse? This is dumb!

Real-World Rating:  7 (Effective)

Cordon of Arrows

You put four arrows on the ground and if anyone comes near them, one of them jumps up and shoots them. A fairly basic trap, kinda cool-looking but not that effective. You know what would be better? Corden of Arrows, a spell that turns irritating talk show hosts into the Wound Man.

Real-World Rating: 3 (Pretty Ineffectual)

Counterspell

Another spell with high value in the D&D world, but absolutely none in the real world. You can't counter a spell if no one but you can cast them!

Real-World Rating: 1 (Worthless)

Create Food and Water

This, conversely, is a spell that's pretty basic in D&D (it basically just erases some minor accounting you'd otherwise have to do during an outdoor adventure or dungeon crawl), but in the real world would be absolutely paradigm-shifting. It lets you create enough food and water to keep fifteen people alive, every time you cast it -- and the water is permanent! That's enough to keep your whole team and a few peripheral personnel alive indefinitely, and is a big step towards removing them from the consumer economy altogether. A boon to anyone, especially wizards who are doomsday preppers, or at least don't like to have to keep making grocery store runs.

Real-World Rating: 8 (Very Effective)

Create or Destroy Water

The lower-level sibling of Create Food and Water, and still valuable, although much less useful. Having a free, permanent source of drinkable water is still very good, but most people can achieve it by just living in an apartment; the aspect where you can make it rain (in the literal sense, not the strip-club sense) is more interesting. Destroying water sounds pretty good, but it's awfully restricted; it just lets you burn off fog -- really only useful in a safe-driving context -- or destroy water that's already in an open container, which you could also accomplish by just knocking the container over.

Real-World Rating: 5 (Effective But Limited)

Create Undead

You might think that this is just a better, flashier version of Animate Dead, but here's where Dungeons & Dragons tries to get you. While Animate Dead can essentially flood the world with skeletons and zombies for the low cost of a single drop of blood per, meaning you can probably have a small army for the price of a Red Cross donation, Create Undead gives you only a single ghoul per two clay pots, pound of grave dirt, gallon of brackish water, and 150-GP onyx gemstone. For all that hassle and expense, you could get a hired goon who brings his own gun. 

Real-World Rating: 4 (More Trouble Than It's Worth)

Creation

You could study for years and years, risking your health and your sanity in carefully cultivating the fiendishly difficult manipulation of the very fabric of nature, and finally become powerful enough to cast a 5th-level spell that lets you warp arcane forces to the point that you can create out of nothing a fully functioning physical object, such as a towel, hammer, or chair that disappears after a day at the most. Or you could just go to the Target and buy that shit.

Real-World Rating: 2 (Mostly Pointless)

Crown of Madness

Since I've started doing this blog, a third category beyond "spells that seem great but suck" and "spells that are unexpectedly awesome" has emerged: spells that don't really do that much, practically speaking, but which are so batshit insane it would be fun to have them in your pocket for the sake of spectacle. This is one of them. It's a pretty low-level spell, and it can be saved against; even if it works to perfection, it just means you get to control them for one minute, in the form of getting them to attack a target of your choice. Not bad (especially useful with high-level opponents), not great (those are the very opponents most likely to resist it), but it literally makes a jagged iron crown appear on their heads as their eyes glow red with insanity. That's fun even if it doesn't do much.

Real-World Rating: 5 (Effective But Limited)

Crusader's Mantle

This makes you glow with holy energy, making your allies inflict extra harm (1d4 damage) on your opponents for a minute. Equally valuable to the bravest of heroes and the most determined of ISIS warriors. Not that great, and probably a bit of a waste for 3rd level, but nothing intrinsically wrong with it.

Real-World Rating: 3 (Pretty Ineffectual)

Cure Wounds

And here it is, the very spell that inspired this blog! In D&D, healing spells (of which Cure Wounds is the foundation) is an extremely minor spell -- basically a throwaway. Any number of classes can use it from the get-go. Translated to a potion, it's the kind of basic buff that scatters the landscape of any RPG or video game. In game terms, this is because PCs get hurt all the time, and they need some easily renewable resource to get them back into fighting trim and ready them for the task of fighting the next opponent. A classic No Big Deal spell, that even clerics rarely give a second thought.

But in the real world? This spell is nothing short of amazing! Just by laying on hands, any living creature, from a panther to a pope, is instantly healed of up to eight points of damage (which, as a reminder, is essentially fatal for most normal humans), from any kind of injury, sickness, poison, or accident! Can you imagine how completely and totally this would alter the whole fabric of modern society? Doctors, surgeons, paramedics, even veterinarians would be driven out of business. Anyone with this power would be the most sought-after person on the planet, rewarded beyond reason -- even if they could only do this once a day, they could save hundreds and hundreds of lives. And if, as is the premise of this whole thing, you were the only person who could do it? Buddy, you could write your own fucking ticket. Not bad for a low-level toss-off that most people pick without even thinking about it.

Real-World Rating: 10 (Essential)

*:  See?  I told you!