Here’s a rundown of things you lose by allowing teleportation magic in a tabletop game world.
The Heroic Journey
Sure, it’s a cliché to say that one plucky little hobbit or a ragtag band of heroes can somehow get through the Empire’s defenses and save the world. But it’s a story of travel and the journey, of obstacles on a grand scale over miles. Maybe that story is easier to tell in film or in novels than it is in tabletop games or video games. But I like having the option to say, “You need to get this princess to that tower before the winter solstice or the Lord of the North Wind will be most displeased with your kingdom” and not have the party just teleport and call it done. There are volumes of wilderness rules and wilderness character types who are denied a chance to shine. Aragorn and rangers generally should be a little put out that a wizard eliminates their role in tales of high adventure. Eliminating time required eliminates the conquest of distance, the raw heroism of getting over the mountains, across the trackless desert, through the badlands, and past the volcano. The physical effort required to get where you are going and be heroic in the Marco Polo mold is gone.
To a certain extent, the teleport spell also reduces the possibilities for exotic travel. Many tales of adventure feature magical travel to the dreamlands, into the afterlife, to the heavens, in spirit form, or animal form. But these methods are still travel. Teleportation deletes the sense of motion because it is easier and more efficient than any of these others. Why travel anywhere in crow form if you can skip all that with one poorly designed spell?
The Passage of Time
The sheer time required to get from place A to place B marks something as a heroic journey. Part of the glory of Alexander the Great is not just that he conquered the known world, but also that he explored it over years. If he had hopped around from battle to battle, he would have had time for a lot more conquering, perhaps, but he also would never have visited midpoints. If the US pioneers had not spent months on the Oregon Trail to travel west, the legends and history of that migration would surely have been very different.
This isn’t to say that you need to spend a lot of table time modeling long journeys. I’m perfectly happy to say, “The journey takes six weeks, and you arrive in high summer,” and move on. However, even if you compress the time at the table—and you certainly should!—I think it’s important to the continuity of a game that players can feel that time has passed, that the journey has turned the wheel of seasons.
This is time compression, which can be as simple as “You spend two weeks on horseback and cover the Rothenian Plains, avoiding raiders and driving off a band of centaurs.” Time compression is a nod to a big world and reinforces the sense of scale. Time elimination destroys that sense of scale, making all places equally distant (which is terribly convenient on the phone and in real life, but terribly mundane in gaming). Spending time on a journey is a way of showing its importance. It’s a bit of a ticking clock that generates challenges of its own. Eliminating time means eliminating seasonal cutoffs, such as “We must get there before snows close the pass!” or “The prevailing winds make the return voyage impossible except in spring. You’re stuck here for the winter, o Great Druid.”
Note that spending time to travel need not be a heroic challenge for every journey. If the PCs want to travel back and forth on fine roads between well-ruled and enlightened kingdoms, they certainly can and should do it without monstrous dangers. But time will keep ticking, and that passage of time is an opportunity for their enemies—which brings us to the third element lost in teleportation magic.
Dilemmas and Trade-Offs
Making it possible to circumvent distance means that players rarely have to make hard choices about where to go, how to split forces, and so forth. Instead, they can fight in the distant demon shrine, teleport, and then fight in their hometown. There’s no need to struggle with a dilemma imposed by distance.
This is similar to the problem of cell phones in films and TV. Until recently, it was possible to have storylines that included information differentials between characters because communication was so difficult. The arrival of cell phones and texting in the 1990s made it increasingly difficult to say that two characters would be unable to share vital information.
Part of the appeal of medieval fantasy, of course, is that modern communications, medicine, travel and so on are not part of the setting. So why would you want to give characters the opportunity to freely hop around the world rather than forcing them to choose their path with care? The lack of teleport leads to greater planning, greater care, and greater caution. The dilemma of presence favors characters who can think and act decisively and correctly. Teleportation allows for lazier, sloppier thinking because the price of movement is so low.