But if no one can provide examples of how your game design made your adventure fun - your use of the rules that you're supposedly an expert in - that's weird. If the audience isn't going to demand that D&D designers create fun play by using the rules, rather than in spite of them, then why are we even calling them "game designers"?
I'm gonna quote myself and refer specifically to my running example from
Radiant Citadel to add more nuance to this.
Once the actual flying carpet chase is underway, the rest of this section of the scenario has some game design stuff in it. It puts limits on how often either participant can Dash before making Constitution checks. This part is a little weird because it's talking about characters who are flying without using a
carpet of flying somehow. If someone has a
carpet of flying, they can't Dash at all. So the escaping wizards can't Dash since they're on a
carpet. Is it likely that at least a few of the PCs are on the extra
carpet of flying? Pretty likely. So, generously, if half the party can fly without the
carpet, they're subject to these Dash rules. Maybe that's good because two PCs can Dash to catch up to the
carpet faster than the others. But then you've split the party, now it's 2-on-2 and the wizards the party's chasing have
fireball. There are also a brief paragraph about targeting spells and attacks.
Is this game design? Yes. But it's
also lifted straight from the DMG's chase rules, so it's not Justice Arman's game design. Why is WotC wasting space republishing the DMG's chase rules in this compressed format when you're already short-handing references to monsters, spells, and magic items? Was there a word count issue?
There is a table of chase complications. You roll 1d10 and on a 1-6, there's a complication. Four of the six complications are reskinned versions of the same mechanism from the DMG's Urban Chase Complications table. The form is generally "make a DC 15 skill check or ten feet of your movement is considered difficult terrain". Two of the encounter's complications call for saving throws rather than skill checks. The design principles of the DMG's Complications table suggests that difficult terrain is the penalty for failing a skill check. The penalty for failing a saving throw is a condition.
One of Arman's conditions is a variation on a standard DMG Complication: make a DC 10 saving throw or fall prone. In the
Radiant Citadel version, it's been tweaked to read:
"A taught line of tenants stretches across your path. You must succeed at a DC 10 Dexterity saving throw, or you fall 2d4x5 feet, taking 1d6 bludgeoning damage per 10 feet fallen and landing
prone. If you are using a
carpet of flying, any character on the same conveyance must make the same saving throw."
The original version of this complication in the DMG only affects one person. This could potentially affect the entire party. There are four classes that are proficient with Dex saving throws: bards, monks, rangers, and rogues. For everyone else, a DC 10 Dexterity saving throw could mean a 45% chance of getting knocked off the
carpet. Dexterity's not often a dump stat for any class, so maybe the odds are a little better. But anyone who fails that roll is potentially out of the scene. Can I say that for sure? Not exactly, because I don't know for sure what size of
carpet is being used by the escaping wizards. If it's the one that moves at 60ft./round, then it's pretty unlikely that a character can continue the chase on foot with their 30ft./round.
Did the designer intend to introduce a complication that could remove more than one PC from the chase with a some bad rolls? There's section called "Ending the Chase" that tells the DM to make Stealth checks for the wizards if they end a turn ahead of the party and out of sight. Are there any design elements in this encounter to model if and when the wizards might be out of sight during a given round? Nope. Admittedly, these are the standard DMG rules for ending a chase. Incidentally, Mages aren't proficient in Stealth, so they've got to rely on their +2 Dex modifier and beat the highest Passive Perception score of any PC in pursuit. It would be great if the wizards had some way of getting advantage on those escape rolls, wouldn't it?
It turns out that there is! The DMG's chase rules have a section called "Ending The Chase" that includes Escape Factors that might give the wizards advantage (or disadvantage). Why has
this part of the DMG's standard rules not been reprinted in
Radiant Citadel?! Everything else basically has been! It's baffling. They've reprinted the DMG chase rules presumably so that the DM doesn't have to flip to the DMG itself, but then omitted some key modifiers that can make the difference between winning and losing the chase. This one's probably on the editors, or Crawford or Perkins, but it all contributes to the pile.
The
other custom complication in this
Radiant Citadel encounter requires that a person make a DC 16 Constitution saving throw or be
blinded for a round.
In addition, the PC must roll on the complications table
again and suffer the result unless they decide not to move for a round. Note that there's a specific, custom rule for this
Radiant Citadel chase, stating that if a complication could affect multiple characters and those characters are all on a
carpet of flying, it's the
carpet's pilot who is affected. (EDIT: Presumably, this is Arman's design.) So this pilot must make a DC 16 Constitution saving throw. That's much harder, especially for a character that's not proficient in Con saves. Now, the pilot can avoid the extra complication penalty by not moving during their turn. Does that mean the whole
carpet can't move? Again, that could doom the party's chances of winning the chase depending on how many of them are on the
carpet. Plus, the
blinded condition says that a character automatically fails any skill check that requires sight, like the ones needed in a chase.
Note, too, that the standard Urban Chase Complication table in the DMG has a 50% chance of generating a complication. You roll a d20 and a complication comes up on a 1-10. In the modified
Radiant Citadel complication table, there's a 60% chance, since you roll 1d10 and have a complication on a 1-6. Two of those six complications are the potential chase-enders with the saving throws. So this chase will have more complications on average than a typical chase run with the DMG's rules. That might be a sensible design choice, but I'm leery. Two of the custom complications are harsher than the ones that the DMG can create and they're going to happen more often on average.
Is Justice Arman's
Radiant Citadel complication table designed with intention and purpose? Does it produce fun and interesting play and is that a result of his efforts? It's hard to say! Most of the complications are straight out of the DMG. A couple have a small twist, and that could be Arman's hand. But the tweaks create a little more risk that a player might make a bad roll and have to sit out the rest of the chase. It doesn't strike me as a fun play pattern. I suppose that could be the outcome of other chase systems in other games, but that echoes something I said earlier. Just because other games' chase systems have potentially unfun features doesn't mean that you can get away with using them in your design.
Does Arman sort of want the wizards to get away? Maybe. The way the scenario's designed, the PCs can fail the chase, but discover where the wizards went by asking if anyone saw a flying carpet and making a DC 12 Persuasion check. So there's no real
cost to losing the chase, so maybe the design itself doesn't matter as much? Throw in the standard DMG rules, tweak a couple of complications to feed your creative soul, and move on?
All of this comes on top of the other flaws in this encounter I identified earlier. These little impressions start to add up. Where is Justice Arman's skill as a game designer in this encounter? Maybe Jeremy Crawford forced him to use the DMG chase rules (as he should, but why waste the word count republishing them, and republishing them incompletely?) and the only opportunity to put his own game design spin on it came in the custom complications. In the two custom complications that seem to have the most visible fingerprints, the changes make it more likely that a player might drop out of the chase. Is that fun? I don't think people would describe it as "fun," but they might say that not every PC needs to be involved in every encounter. It happens in D&D. But after a fight, a chase is one of the most exciting sorts of encounters in a D&D game. It's not great that the designer's tweaks shift the balance away from all players participating.
In the hands of a designer I have more confidence in, I can see past this sort of thing. But this entire encounter's a bit of a wreck, top to bottom. Once I lose a little of that confidence, it's hard to get it back. Some of the possible missteps, like the modifications to the complications, are closer to judgment calls. But the stuff about the different speeds of
carpets of flying, the environment when the chase starts, ignoring the spells available to the expert wizards performing this theft, those are more basic mistakes. If the designer can't get the basic stuff right, I can't help but withhold the benefit of the doubt for the judgment calls.
EDIT: It occurred to me later that the custom chase complication with the chance to blind a participant is a good example of mistaking "thematic" design for good game design. The flavor text for this complication says that "spices from an overturned table fill the air." So that's what's going to potentially blind a character that triggers this complication. Thematically, that makes sense. Blinding cloud of spice gets in your eyes? You might be blinded. But this isn't "blinded", it's
blinded, just like it's not a "flying carpet", but a
carpet of flying. If the pilot of the
carpet of flying suffers from the
blinded condition and the DM's trying to use the game's rules, then the pilot's decision is really "Should I risk the chance that I might have to make a skill check that requires sight - like following the escaping wizards - and automatically fail that skill check, or should I stop this
carpet for a round and put everyone who's on it further behind in the chase?" The difference between "blinded" and
blinded has a real impact on what that pilot player's going to do. It's a crappy decision to have to make if you're the player. How often will this happen in play? It might not happen at all. But the potential is there in the design. Did the designer intend for that potential to be there? Maybe Arman thought the probability of the worst outcome was pretty low and that the overall design of the chase is better if this trickier complication is included. That's a judgment call, too.