I really hope this thread gets noticed by the devs. I found a few typos and a few things that I would like to see clarified.
"Rolling 20 is better!" on page 8 seems to suggest that all you need for a critical success is a natural 20. p.292 says you need a natural 20 and a success.
There's a lot to be positive about. I like the quality of the flip-mat multi pack! All four of the maps are extremely cool, and I absolutely love when a published map syncs with a published adventure. Please PLEASE make that happen more often!
As for the recent spate of negativity, it might just be highly opinionated people's first impressions. Still, first impressions mean a lot. Maybe it was not a great idea to publish this playtest at a time when most of the Paizo staff is away at GenCon. According to a post by Vic Wertz (the CTO), they don't plan to respond to most of the forum postings until after Gencon ends and things calm down. I think this is a marketing error. Here's a chance for Paizo to really get out in front of the bad reviews and aggressively market the things that the playtest does well (again, there are many things the playtest does well!). But they didn't, and that's a missed opportunity.
I would say that I greatly support the "spirit" of making the game modular. As for the execution, there are some rough spots.
Could you please explain what you meant about barbarians and rogues being the baseline for classes?
I agree that the current system of "escalating DCs" in the playtest is overly-complicated. The table on page 337 is maddening. It reminds me of the THAC0 tables from AD&D2e. It's not well explained thematically, and it could lead to abuse (hopefully unintentional) abuse by the players or the GM. As other's on the linked posts have pointed out, the GM may not remember what DC was set for a task between play sessions, and the escalating DCs table is not flat enough to easily remember your logic in picking a DC. There's also the problem of making the DCs secret, which might cause some distrust among the players.
This system of escalating DCs makes me uneasy about GMing a game. The hardest part of GMing (in my opinion) is adjudicating rules that aren't in the rulebook. When your players ask to do something unconventional, you should be able to shoe-horn it in to an existing rule in a way that both rewards creativity and is fair to others who might try the same thing. But then you have to come up with a DC for this unconventional rule, and the system breaks down.
I do agree that a system of bounded accuracy would be nice. I don't love the way that D&D 5e lumps everything unconventional into an ability score check. In my opinion, ability checks are not the answer - skills (and maybe feats) are the answer. But the current treadmill of +1 per level is anything but bounded, and the system of adjudicating DCs suffers mightily because of it.
I agree with a lot of the points in this thread, and I'd like to respond to a bunch of points all at once.
I really like the modular approach of PF2e. I think the modularity is especially effective when it comes to spell heightening and cantrips.
Here's where I think PF2e could really really stand out. Give us a more modular system of encounter building! The playtest bestiary says that a party of four characters can fight monsters that range between the party level - 4 to the party level + 4. That seems a bit dubious given the small number of bestiary entries; I predict that most encounters will range from level - 2 to level + 2. That's quite a nice spread of 5 monster levels, but I think they could do things differently for more effect. In fact, since the playtest bestiary monster entries are so static, I have serious doubts that four level zero enemies will actually produce an equal threat to one level four enemy. (I haven't thoroughly playtested that particular issue, just looked at monster entries.)
Maybe that's asking a lot, but this hasn't been done well before. If paizo could come up with a good modular system of monsters, it would be huge.
As for XP rewards. I don't see any problem with it mathematically. They switched from a quadratic progression to a linear progression. That way at every level, fighting a creature of the appropriate level gives you the same amount of XP. This could be a very good thing for modularity, but to reiterate what I said above, they did not go far enough in making the bestiary monsters modular.
Lastly, I agree with above posters that PF2e's current approach to bounded accuracy (escalating DCs) is not going to work out. In particular, the table on page 337 is an absolute ABOMINATION! Having to use that table actively discourages me from GMing a 2e game. I predict that the table will cause play to grind to a halt whenever death saving throws come up. But I plan to write a separate thread on this topic.
If you're really worried about die fairness, then you shouldn't fuss about the manufacturing method of your die so much as you should worry about your die in particular. (Many people have already mentioned that defects in the plastic, settling, and other small variance can make even the most carefully crafted dice biased).
As long as your dice are fair according to this formula, you shouldn't care how the edges are distributed. Here fairness means that your dice are random within a very small margin of error. Even "electronic dice" (i.e. dice rolling apps) aren't truly random, because it's been known for a while that computers aren't able to produce totally random data. So at some point you'll have to live with almost random.
The only caveat would be the way that you roll your dice. Some people have perfected the art of rolling a spindown die so that it rolls high, but this sort of behavior should be noticeable to an observant DM. To ensure that your dice rolling technique is sufficiently random, it's best to cup your hands together with the dice inside and shake your cupped hands up and down or side to side. I think three shakes is enough to ensure your rolls are highly randomized, but again you can increase this number if you'd like.
That's my take on dice randomness. Math always saves the day.