What can I say. I don't think this is necessary, form follows function and all that. I can't think of much of anything in the book that would be particularly confusing.
Because, as I have said many times, 5e was a system written for old hands. It was not a system written for the young, the inexperienced, the unsure, or the only middling-skilled. It is, in general, unwise to write your fundamental guidebooks specifically for people who already know what to do. It is, in general, better to write your fundamental guidebooks for people who have no idea what they're doing and thus significantly benefit from having things explained to them.
That doesn't mean you can afford to
ignore the old hands. They're your long-time customers, you need to speak to them too. But for the
core books? No. Those need to be for the folks who don't yet know what they're doing.
Books like the Rules Compendium, on the other hand, are
great if they're written for old hands. Because then they can just be lean, mean rules machines, unadorned and easily-referenced.
Again, I think the subsystems pretty much speak for themselves.
I assure you, they do not.
Not sure why you need to state this any more than it already is. There's a fair amount in the DMG on how to run the game. The Role of the Dice goes into it for example. They discuss, for example, that PCs shouldn't have rare items until at least 5th level but it's just a suggestion. There should be more, it goes along with the wealth table.
"But it's just a suggestion" is exactly the problem. It is barely anything at all, and certainly not the kind of useful advice that helps fresh DMs get into the process quickly and smoothly. Or fresh players, for that matter.
If all the hooting and hollering about 5e's dramatic success is to be taken seriously, something like 90% of current D&D players are brand-new to the game. I think it would be significantly better if the books were written for that 90% of players, and not the 10% who already know what they're doing and thus barely even need books to begin with.
The price list back in old school DM? It was just numbers thrown in with little to no logic. There has never been a very coherent price or rarity system in D&D. On the other hand between the DMG and XGtE we have it.
Ah, that word, "never." Such a curious thing, isn't it? Rather depends on how you view the subject. I certainly don't agree with you that it has never been done.
Everyone knows the DMG needs to be redone, the devs have stated it multiple times. We'll see what we get later this year.
Not at all. I still to this day see people asserting that the 5e DMG is one of the best ever written. It took literally ~7 years before people even
remotely took seriously the idea that the 5e DMG was badly written. Voicing any criticism of it at all was met with incredulity at best and outright laughter at worst. I was very specifically told, on this very forum, that a book labelled "Dungeon Master's
Guide" did not need to have any "guidance" in it whatsoever for dungeon masters. Multiple people agreed with this assessment.
So yeah. It's nowhere near the universal agreement you claim it is, and people have been burying their heads in the sand about it for most of the past decade. I am, as a result,
extremely skeptical that the 5.5e DMG will be meaningfully different. Would be nice to be surprised, though.