I’ve run most of the first-party 5e APs at this point, and I don’t have extremely detailed thoughts on them, but I can probably squeeze a post out of sticking them all together.
Tyranny of Dragons: A grand tour of the Sword Coast is not a terrible premise to have for your very first AP of a new edition, and using dragons as the main villain also makes sense. The weird rules inconsistencies that exist as artifacts of having made the campaign while the rules were still in flux are forgivable. Less forgivable is how much of a massive railroad the whole thing is. I wish it had been more open, like Storm King’s Thunder.
Lost Mine of Phandelver: This is a really good, fairly open adventure that focuses on a specific area and really builds your connection there, while also seeding in connections with the five player-facing factions of the game, which serve as recurring allies (some shadier than others) throughout all the APs, which is a cool idea by itself. There is one major flaw: Your employer being kidnapped but possibly still alive in the hands of some nefarious goblins gives you strong incentive to try and track him down ASAP. This is a terrible idea! You’re supposed to bum around the area chasing side quests for a while to get another level or two first. It would really benefit from the employer being saved (or confirmed dead) immediately after the initial goblin dungeon, and the party being given a less urgent but still pressing objective of “find out what these goblins are up to.”
Princes of the Apocalypse: I haven’t run this one. The cults of Elemental Evil are all individually cool in concept and look neat, but the adventure itself seems like it might be a bit of a slog by the end, with four consecutive dungeon crawls? As mentioned, however, I haven’t actually run it, so it might have more momentum than I’m guessing or I may even have completely misinterpreted how it works (I’m not rereading the entire adventure for this quickie blog post, so I’m going purely off of memory of having read through it once to see if there were ideas I could pillage for other campaigns/projects). I do like that it again has a fairly local focus on the immediate environs of Waterdeep, which (hopefully) allows you to get feel more involved with the area under threat, with personal connections to specific NPCs, rather than just “innocent people as an abstract concept are in danger.”
Out of the Abyss: This is one of my favorites. A fairly open exploration of the Underdark full of interesting NPCs, strange locales, and making good use of both demons and dark elves, who are both pretty solid villains. My only major complaint is that the climax involves an apocalpytic confrontation between demon princes that happens almost completely without player involvement, and then they just mop up Demogorgon at the end. While having a boss rush of all eight demon princes in the book would almost certainly TPK anyone, I think having a cataclysmic confrontation in which the PCs must navigate Menzoberranzan while it is being attacked by all eight demon princes at once, each of whom is also fighting the others, would have been a great place to showcase each of the eight demon princes’ forces (or themselves) in action, while the conflict between each other and the dark elves would’ve given the PCs an edge in getting through without being too beat up to take on the last man standing at the end.
Curse of Strahd: Another one I haven’t run, although in this case that’s because it’s so popular that everyone has already played it. Other people have talked about the problems with the Romani-coded Vistani, and this one-paragraph summary isn’t really big enough to get into it except to say that yes, that is a problem. Overall, this is a very open adventure in a setting that I love with a tragic villain. It’s not a surprise that it’s amongst the most popular, and I hope I get a chance to run it sometime.
Storm King’s Thunder: This is another open adventure, this time taking place across the Sword Coast, but it has a baffling design decision (which we haven’t seen the last of) in that it has multiple points where you can do one of three or five different quest hooks and not the others. Three towns get attacked by giants and it is expected you can save one of them, and you can get access to the storm giants’ palace through any one of five different giant strongholds and have no reason to visit any of the others once you do. What’s the purpose of this? Do you think people are going to replay the same campaign multiple times like it’s a video game? D&D is way too logistically difficult to waste sessions on replaying the opening of a campaign you’ve already done just so you can get to the new content later on. The campaign should be restructured so that it makes sense to do all the content in one playthrough (although you should be able to skip some of it if you want – five is a lot of giant strongholds).
Tales From the Yawning Portal/Ghosts of Saltmarsh/Candlekeep Mysteries: These are all adventure anthologies, often with different authors. This is a neat idea since individual adventure ideas can either be torn out to use in other campaigns or be stitched together into one narrative, within an anthology or between them. It does mean that there’s not really a whole lot to say, other than that Ghosts of Saltmarsh’s ship rules were disappointing and the anthology adventures gave basically no reason to ever use any of them anyway.
Tomb of Annihilation: All the content in this adventure is individually awesome, but the hexcrawl is a trainwreck. Less than 10% of the hexes have encounters in them, the survival mechanics are more bookkeeping than interesting choice, and you can spend a lot of time bumping into random encounters, which can be absurdly lethal for low-level parties (who very much are expected to go out into the wilderness – that, or they did a terrible job of signaling that you should stick to the starting port until level ~5). Revamping this adventure into a pointcrawl drastically improves it.
Dragon Heist: People love the hook of owning your own tavern and of an urban heist adventure. I’m in the minority on this, but I think this adventure actually does a pretty bad job of delivering on both of those promises. This adventure also continues Storm King’s Thunder’s weird trend of having lots of good content split up into different, mutually exclusive versions of the campaign. Instead of having four different antagonists after the same thing, they demand you pick one. The Alexandrian has a remixed version that uses all four villains simultaneously.
Dungeon of the Mad Mage: Megadungeons are always tricky. The concept is great, it takes the most iconic setting of D&D (“dungeon” is in the name!) and expands it out to an epic scope. Many D&D campaigns are essentially a dungeon anthology where a metaplot strings lots of 1-3 level dungeons together. Why not stack those dungeons on top of each other? Rappan Athuk does this really well. Dungeon of the Mad Mage does not. There’s just not enough interesting stuff in here to justify fifteen levels of dungeon, and the path through the dungeon is too linear, without enough connections between levels, side-levels, or hidden entrances leading to deeper levels. Amateur game designers used to talk all the time about making their tabletop game like Dark Souls, and they always talked about making it lethal or, even worse, trying to make a group game lonely. What people should actually be looking at is that game’s level design, which actually does have some very good lessons to teach about making dungeons.
Descent Into Avernus: The hook on this is fantastic. Baldur’s Gate is the single most popular D&D city ever (courtesy of BioWare) and the basic concept of going into Avernus to piece together the history of its tragic angel-turned-archdevil ruler by way of recovering her hollyphant companion’s lost memories is pure gold. Unfortunately, it’s also an interminable railroad. When I ran it, I edited it to be much more open, which I think worked pretty well.
Rime of the Frostmaiden: This is a really well designed adventure. As with the other hits on this list, it’s very open and has tons of interesting content to be discovered in that open space. It does narrow down in the second half becoming much more linear. You want some amount of racing towards the climax at the end, but I think the linear sections drag on way too long to serve that purpose. The problems with the linear ending notwithstanding, this is another focused exploratory adventure in a new and fairly unique setting, which has reliably been the key to success at least for first party adventures (it’s hypothetically possible, I think, to have a good linear adventure – but I think anyone who can do that will write novels instead, because novels aren’t attached to a specific edition of a specific game and become less valuable when that game becomes unpopular).