Without having seen the book, can I just say this as a general response to any calls for harder modules or more lethal dungeons: not every player is a 30-year grognard who picks their racial ability bonuses to match their class, and browses charops boards for ways to abuse contagion.
D&D modules should be designed for 13-16 year-old players who have been RPGing for less than a year. End of story. That is the only way we grow, or even maintain, the brand. The teenagers who started out with 1e and OD&D (ahem... like me...) are getting long in the tooth, now. And we're experienced enough to recognize and pump up the difficulty of a module when we need to.
If I look at the criticisms in this thread, I see three issues (beyond the use of Yawning Portal as a framing device, which is fair enough):
1) Too many magic items. Great! The teenage players will love the magic items. Who doesn't love finding exciting new gear? For us old dogs, it is the work of seconds to remove a few items from the troves. As a DM, I'm not going to give a +2 axe to a 2nd level character (unless I want to). It is no skin off my chin to simply remove it from the 200-page module. Meanwhile, some parent's 11 year-old daughter's eyes are going to light the hell up when her kick-ass red-haired elven fighter picks up an awesome magical weapon. Good outcome.
2) Not enough death-no-save lethality in Tomb of Horrors. Great! In 2017, ToH as written is a crap module - and that's speaking from the perspective of someone who grew up with it, and DM'ed it, and loved it. I also loved Dukes of Hazzard when I was a kid, and that's also pretty crap in 2017. Tastes change. If you want the original ToH, you've got the original ToH. Nobody can ever take that away from you. However, awesome people have now re-designed the module so that the essence is still there (purpose-built dungeon-o-traps) without all of the aggravation. No more DM-as-antagonist, no more describing every action you take in excruciating detail, no more rolling up more characters because you didn't second-guess the designer, and no more reliance on the party cleric or wizard. And for everyone who has ever said that ToH rewarded intelligent play: no, it didn't. It rewarded boring play, with 10' poles and summoned creatures testing every inch before proceeding. And clerics and wizards spamming divination spells. Half the traps in the original ToH could be avoided by a simple detect magic and a bunch of mook summons.
3) High level 5e D&D isn't hard. Hogwash. It's as hard as your DM makes it. My group of 20 year veterans has eleven TPKs to their name since 5e started, and most of those occurred between 10th-14th level. The fact that there are no magic item creation rules (thank god) means that items are as rare as the DM chooses to make them, and many items will never be available. Upset about revivify and raise dead? There's a diamond shortage. Players in my campaigns know that diamonds are almost impossible to obtain, and an NPC raise dead is about as frequent as a Chaotic Evil flumph. Most characters don't see a magic weapon in their entire career, which makes damage resistances a real issue. If they find magic weapons, that's not on the module - it's on the DM. And again, high level D&D should be written for the teenagers. If you're finding it too easy as a pro, then you should have a pro DM who knows how to ramp up the difficulty level.
None of the concerns above will worry me about Yawning Portal. I want it to be easy, and a good champion for bringing more kids and casual players into our hobby. For my own games, the only thing I want from it is clarity (nice maps, simple room descriptions), ease-of-use, and some evocative characters and set-pieces.
