Which is why I said not allowing the party to always dictate the pace of play is essential. They teleport, rest and then bust in on the BBEG who has had 8 extra HOURS to prepare or, more likely, has moved.
The key is to make sure the PCs see teleport as a convenience not as a game buster.
Well if they hadn't teleported, the bad guy probably would have had weeks prepare instead of mere hours.
Yeah I feel like you aren't really listening to Crimson Longinus here, Mort. It can take days, even weeks to travel the distance that
teleport can cover in but a single action. Even if you throw in 20 minutes to cast and fully exploit
scrying and then eight hours' bed rest to be in full fighting shape, there's...just really no way that overland travel isn't going to take longer to achieve the same end.
It's just a recognition that the game changes at high level. If regular joes kidnap the PCs friend, they get what they get. If people prepared for the PCs do that - it's a bit of a different story.
But yes you generally have 2 options when dealing with high level play. Ban any offending spells, or roll with them and accept the PCs might obviate/bypass a larger % of challenges than they did before. Generally, I choose to embrace the PCs bypassing stuff - makes them really see they have advanced - and forces me to think about challenges differently.
The problem is, with the highest three levels of spells, the percent of challenges they obviate/bypass becomes exceedingly large. As in, almost everything has some spell it can be obviated by. Yes, it's true that not every caster will have them, but a diverse party with at least two distinct full spellcasters is likely to have most of them, and three almost certainly will, once they're high enough level.
I'm not saying that it's bad that DMs should need to plan. I'm saying that the excessive degree to which most things that would qualify as interesting stakes become obviated is...well, a problem. A pretty big one,a ctually.
I simply say that the teleport spell is highly unreliable - even sometimes in cases where you know the target. In addition, if you take an object from a location it has to be something iconic and unique to that area, it can't just be a rock from the side of the road.
In other words, you actively nerf the spell so that it merely has a
chance to obviate things--which is what I already said. You make the tool crappy, so there's never really any desire to use it, which is just soft-banning it. E.g., your requirement that the object be "iconic" is simply a straight-up nerf to the text of the spell, which explicitly says that "a chunk of marble from a lich's tomb" is a perfectly valid "associated object." It isn't the only not-very-emblematic thing either, as it also mentions bedclothes and library books, neither of which is guaranteed to be so precisely identifiable with a specific place. How is this not an admission that teleportation, as it stands in the rules, is a problem that needs to be curtailed?
Sigils for teleportation circles do exist, but they're typically a tightly guarded secret for a good reason; you don't automatically learn any sigils it will be dependent on what you would logically know. I also let the PCs cast it as a ritual because it's pretty rarely useful.
Note that we are speaking of
teleport, rather than
teleportation circle. The former is a 7th-level spell that does not require such sigils (though using them skips the "roll to see how close you got" part, same as having an "associated object")
But I agree with the whole travel from A to B can be part of the fun. Why have a flying ship if you can just pop from one location to the next? I also have pathways that allow fast travel similar to The Ways from the Wheel of Time books. I also limit plane shift, but that's more for thematic reasons because I base my cosmology on Norse myths. Why have a guardian of the Asgard bridge if anyone can just planeshift wherever they want? So you have to find a portal or a weak spot between the worlds for the Feywild or Shadowfell.
All of which are cool, flavorful, reasonable choices...
that are nerfs to these spells so they won't be so broken. You are taking one of the two paths I already outlined. Either you take away the toys to some degree (nerfing, banning, narrowing, etc.), or you get into an arms race over them.
I also think I mentioned on above that Plane Shift doesn't let you go to a specific location, it sends you do a general location. Depending on where you're going that could be quite hazardous.
Which sounds like straight-up adversarial DMing. "Oh, you used that spell that explicitly does something that would mess up this stuff? Well guess what now you're dropped in a lake of fire
next to the City of Brass!" I doubt you would actually do something
that petty, but that's merely an extreme demonstration of the logic going on here. The players used a tool that was inappropriate, so they must be punished by having to face some kind of danger. Why not alter the tool so it
isn't inappropriate? Why have all these ad-hoc, post-facto nerfs and patches and punishments when you could just....have it actually be part of playing the game that these things are difficult and need time and preparation, rather than a fire-and-forget spell slot?