Terms and concepts are introduced without explanation of what they are (Proficiency Bonus being an example). Their use gets explained a few hundred pages later, if at all.
Tables are pages away from the text that references them, and some things are left flatly undefined.
5e was striving for a more 'natural language' feel after the jargon-dense 4e and RAW-litigation of 3.x/PF.
the book itself seems to be written for someone who already knows the system or the concepts.
The target audience for 5e, as just came up in another thread, was 'everyone who ever loved D&D,' so, yeah, between that and having a free basic PDF for people to try first, it's not completely unreasonable to assume some familiarity. I'm not sure the PH really does that, but I've been playing D&D since 1980, so I've lost any ability to judge...
Odd observation: Some parts of common labor, such as sailors hoisting a yard arm aloft or weighing anchor can't possibly be done under the rules.
The assumption is that the DM would make a ruling. Like, if the 20 STR hero wants to hoist the yard-arm himself, he makes some difficult check, if the usual number of able seamen do it, there's no check.
I haven't tried the Advantage/Disadvantage system since play test, but functionally it skews the results severely in the case of any difficult task.
Not so much. Mathematically, Adv/Dis has the greatest impact on even-money checks. If you need to roll an 11 to succeed, advantage is like having a +5 bonus. But, if you need a 20 to succeed or a 1 to fail, advantage is mathematically equivalent to about a +1.
The rules describe Advantage and Disadvantage situations generally, but give no specifics, which again makes it hard for a player, in both a strategic and tactical sense, to plan anything.
It is mostly up to the DM to rule on things like that. Players will get to know a given DM over time, though...
Also, it's a partial list of examples, not what I would consider playable rules.
Another nifty 5e developer catch-phrase is 'rulings not rules,' 5e is meant to run on the DM's judgement more than adherence to the letter of the rules.
Perhaps someone can answer this for me: I have a character who wants to have some skill as a jeweler. How is that represented in the game? None of the skills seem to apply.
Probably in the character's background, like Guild Artisan or something, and proficiency in the tools of that trade.
While looking at a Cleric build, I began to wonder: Are all the spell casting PC classes glass cannon?
No & Yes. No, casters can be reasonably tough, not made of glass or glass-jawed. And, Yes, spells are powerful, but because they're a limited resource that must be managed over a 6-8 encounter day.
I did notice that Saves are very different. If it's one of your "Proficient" Saves, you get Ability modifier and Proficiency bonus, which means that it goes up in level over time. The other Saves (and there are six of them, one for each stat) never advance. So if you have a 10 Wis, for example, and your character class doesn't list that as one of your Proficient Saves, you're stuck at +0 on the roll forever. The DC for Saves, on the other hand, continue to advance, since the target number is 8 plus Ability mod plus proficiency modifier.
Yes, that was an unfortunate design choice, IMHO. One variant I like is to add a +1 to +4 bonus (ie Proficiency -2) over 20 levels to non-proficient saves.
OTOH, saves are rarely save-or-die in 5e, so failing saves constantly even at 20th level isn't entirely untenable.
It goes on. We'll play a few more times, I'm sure, but I don't see a real future in characters that are half frozen in time, with no advancement for half of what they are.
Advancement in terms of checks is intentionally limited in 5e, a design doctrine called 'Bounded Accuracy' that's gone over pretty well with the community (as has Adv/Dis, which you also seemed leery of), in general. The idea is that, regardless of level, PCs/NPCs/Monsters will always be able to interact on the same scale, thus you can run in a fairly stable world, rather than moving the PCs from low-level to high-level 'areas' or even to other planes to challenge them, and you can use the same stable of monsters & NPCs for a whole campaign.
Thus, while PCs don't advance in everything, they don't 'need' to.