Now that the first book has been finished, I think I can talk a bit about it. I can't really remember the last time I played through a campaign book so I'll probably end up comparing this to actual PC RPGs or JRPGs instead. Warning, spoilers.
The first thing you need to know about HoTDQ is that you fight Dragons. Kind of... I mean, you start off as a Level 1 character and you don't actually fight any dragons until way later in the book. So really it's more like, you 'eventually' fight Dragons.
The book itself is segmented into several chapters and is meant for levels 1-8. It even implies that DMs make sure that characters are certain levels after certain chapters. Which is both good and bad. Good because sometimes you want that certain level but you either missed a quest or you didn't complete it optimally. Bad because if you're just going to throw levels at me when I hit a checkpoint, I'll probably just talk my way through the entire frigging campaign and avoid fights if I can.
The action starts from the very first moment, with your characters being thrown into the siege of a town. With that, your lowly level 1 characters have to travel throughout the town, killing kobolds, until you reach the safety of the keep. And then you have to travel outside of the keep again to complete several sidequests for the governor of the keep. This is one of the few chapters which have sidequests while the others are very very straightforward.
In fact, probably too straightforward. The issue may simply be that HoTDQ is very very linear in most ways, and doesn't quite take into account party make-up at times, as well as giving DMs very little guide on how to make encounters tougher or easier for certain parties. As an example, two groups at my local store were playing this campaign simultaneously. One group was Fighter, Fighter, Cleric, Paladin. The other group was Bard, Rogue, Sorceror and Monk. All pure classes. The first group basically steamrolled through the chapters because at its heart, HoTDQ is a very combat intensive campaign, while the other group struggled at times. There are not enough options where players can talk their way through the campaign, especially if the DM is strictly following the book and just giving them encounters as the book says.
And quite frankly, there doesn't seem to be enough of a variation in the types of enemies you fight. I only really remember killing cultists mostly and maybe other stuff 10% of the time. It's really just lots and lots of cultists. And then Dragons. It really feels like they could have used a bit more monster variety in the book. That and more sidequests because sometimes you just need a bit more variety in what your character is doing other than 'beating cultists'. Or 'tracking cultists'. Or 'interrogating cultists'.
Which brings me to another point. Why are all the monster stats not included in the book? Granted, it's downloadable as a free PDF on the web, but why is it not included in the book? A few more pages wouldn't have cost much more to print and not everyone wants to download and print the PDF themselves. It's even worse if you're trying to run the game for the first time and you have NO idea a supplement is needed to 'finish' the book. Then you're forced to go online with your phone and DL the PDF.
In all honesty, it sometimes feels like HoTDQ is a very long prelude to the real book, which is Rise of Tiamat and it feels like they should have just combined the 2 books together instead. Mostly because of the unsatisfying way it ends, which is basically 'Oh hey, you killed this person. But guess what? Cult still doing their thing'.