I just re-read your original question here and realize that not a lot of the discussion so far has been responsive to the last question "Is something about it unclear?". I would now like to provide my answer to that.
It is obviously very well and carefully thought out, however I would like it to be more "glass is half full" than "glass is half empty" in style. I recommend that it start with a positive statement instead of "the following ... doesn't apply to most WikiTree members".
After that statement, it identifies 2 types of members - at high and low end of technical skills - for whom it *is* intended, but does not have different content for these 2 groups.
I also have an issue with the statement about things not being recommended unless they are specifically recommended, which had me scratching my head to figure out what it meant - at first, it sounded like some kind of riddle to me. Although I suppose it might not be technically correct to say this is unclear since I did manage to extract a clear meaning (after considerable thought), it is certainly not immediately clear upon reading the words.
I think reader impressions will be more positive if the wording establishes a more positive feeling, even if the actual content is identical.
Since html is among the "not recommended", I see no reason to confuse things by including comparison of how to do the same thing in both wiki markup and html markup. I would prefer to see ONLY what is recommended presented here, although I suppose a brief statement at the end of the presentation that says something like "this is accomplished in html by use of the <whatever> tag".
I would like to see the presentation of EVERY SINGLE ELEMENT that is "recommended" included on this page. I would like to see the elements grouped by some commonality, i.e., a group for elements that change text appearance (large/small, bold, italic, indents), a group for lists, a group for organizing data displays, etc. I would also like to see the same style of presentation for each element, which would be:
1. The name of the element and a brief description of what it does and the situations when it is good to use.
2. A sample of the code that would be used.
3. An illustration of the result of using the sample code.
4. An explanation of the characters used in the code - where they need to be placed, why, and exactly what each one does.
Numbers 2 and 3 of those are there now. Number 4 would probably be good for the WikiTree members who are currently excluded from your intended audience of this page - those members who do not know how to do these things, but would like to learn how in order to enhance profiles they work on instead of just being able to figure out how to avoid breaking things they see in existing profiles.
Finally, under your heading "Wiki Mark-up is Standard", you say that "all wiki mark-up tags can be considered standard" unless they are recommended against on a WikiTree help or style page, with links to the index pages for "help" and "style". There are a lot of pages in both of those categories, and I think it is extremely unreasonable to ask anyone to go read all of them to try to find out which wiki mark-up tags are recommended against.
If ALL tags that are recommended are on this page then, by definition, if a tag is not on this page, it is not recommended. We need this kind of clear, direct, and easy to find answer when we wonder if we can use a particular tag, and also to immediately see how to use it.
If you give me a list of ALL recommended elements, I will be happy to provide a draft of items to identify, give examples, and describe the code used for them. You can then work on whatever changes are necessary/desirable to what I produce to ensure that the result is clear, concise, technically correct, and user friendly, I like to think I'm pretty good at translating technobabble to English, but the bottom line is that I am an engineer, not a creative writer.
I hope you don't take this (painfully long, for which I apologize) comment as criticism. You obviously have a lot of work invested in that page already and what I'm suggesting is more in the nature of fine tuning than any kind of changes.