My interpretation of this is that Wizards should seriously consider shifting power levels further down the line a bit. Having access to stuff like Plane Shift might be really cool for the player, but those sorts of spells tend to restrict the nature of adventures that can be run. As it currently stands, adventure designs really kind of start to break down by about level 12, as more and more caster classes gain abilities that allow for total bypassing of content.
I'm not sure I see their current adventure design differing substantially from what the results of those surveys would indicate. The adventures have been in the 1-15 range, trending towards the middle levels due to some starting at 3rd, and 1st and 2nd level being lightning fast even if they don't. So a little bit is spent in tier 1, most of the time is spent in tier 2, then some time is spent in tier 3.
If WotC were to end their campaign adventures earlier that would just eliminate 5e published options for tier 3, which isn't what I see is what people want from those charts. What they need to do is include tier 4 somewhere.
On one hand, players might think "well that's not so bad, because we're using our abilities and it feels really good to know they were effective." But for people writing adventures, and the GM's having to prepare them in advance, it's usually not a great feeling to see hours worth of content skipped because the druid turned everyone into a cloud and flew past it. So then it becomes a matter of having to anticipate what your player's can do, and plan accordingly; for published adventure where you can make no assumptions about group makeup or spell selection, that's not possible.
Yep, it will be a challenge for designers. They will have to make adventures that are both fairly open, and rely on things the PCs intentionally choose to do and places they intentionally choose to be (note I said
be not
go, because we're talking about motivation to adventure somewhere). I think it should be done though. By "a challenge" I mean that in the positive sense of something to be striven for, not the sense of being too difficult to be worth it. Perhaps reviewing older edition high-level adventures could help. Or maybe just brainstorming sessions where some of the people pretend they are playing high level PCs and they bounce around ideas with the player proxies having no input other than to point out how they will bypass the challenges of the adventure. It isn't about coming up with a way to stop the players from everything they want to accomplish, but rather making what the players want to do and what the adventure wants them to do coincide.
A high level adventure needs to be
different. Sure, you can just have a 20th level dungeon crawl every now and again, but if you want to really take advantage of high level opportunities you'll want to liberally use politics, planes and principles.
Politics: The PCs could be assumed to be powerful individuals in more than just the "guys you hire to kill monsters" sense. They are movers and shakers of the world, with the sorts of stuff that name level PCs had in older editions. So the politics isn't just about the duke plotting against the king, it may be that
"...if possible, this infiltration will happen in a domain under the rulership of one of the PCs..." or
"...one or more of the PCs' most powerful rivals (perhaps resurrected if they've already been slain) should unite with the Cabal, bringing all of their resources and influence with them...". And it definitely will be on the scale of
"...should the PCs fail to prevent the assassinations, a devastating war between the empires is almost certain to occur..."
Planes: There aren't really a lot of resources clearly putting together the possibilities of high level planar adventures that I'm aware of. Most planar materials are great, but scattered around, so that makes it difficult. Perhaps an "Elminster's Guide to the Planes" with chapter one being about the societies of the exemplar major planar races (with descriptions of the composition of their armies, etc), would work out. Or maybe just a new Planescape book that included more focus on high-level play. The materials are there, but it takes some work to get it all put together. But when you do, you can knock everything up to the next level. Even dungeon crawls can be epic and still make sense out on the planes.
Principles: Step back from the nitty gritty of the adventure, and think first in terms of absolute principles. Not just Good vs. Evil (though keep that), but all sorts of other questions, paradoxes, etc. Then weave the entire adventure around it. Imagine a puzzle from a sphinx that is a pain to answer. It might normally get you looking for other ways around it. If the puzzle is clearly designed so that solving it the "right way" rather than cheating with powers is a test of moral character/resolve/etc, it might normally just annoy the players But what if the entire adventure is designed around exactly those sorts of questions. Now you aren't trying to cheat at the riddle (unless that is one of the themes being explored), because you are willingly participating in the premise. And there is no reason in such a situation to directly punish characters for finding a way to power cheat if they find one anyway, because solving it with guile might in and of itself inform important elements of such an adventure. Is solving that puzzle with guile rather than resolve the message you want to send to the moral fabric of the cosmos? Maybe it is. The players get to decide, and a cool adventure event happens either way.
In these adventures, make death just be a speed bump. Or better yet, make it be part of the journey.
Now, not everyone is going to want to play these adventures. They aren't for everyone. But neither was the Planescape: Torment computer game, and that is a real masterpiece.
So, basically, don't try to make high level adventures the same as low level adventures with bigger numbers and special effects. Make them into something entirely different that actually
works with the capabilities of characters at those levels.
I don't see this core problem being solved until Wizards is willing to get rid of the golden goose that is Wizard spell progression. Things would be totally different if the real crazy spells were held off until 16+.
That would be a real let down for me.
