This is a point which was subject of lot of discussion since years in several forums. Even this uservoice mentions it (partly) sometime but obviously it hasn't been considered at all.
In InDesign, a footnote can't contain xml structures.
In InDesign, it is not possible to map an xml element to the footnote object.
This is really weird, since:
a) mapping XML element to an InDesign object is something exiting already for tables thanks to attribute aid:table. So why not having set an attribute aid:note, with values "footnote" and "endnote" and implementing this?
b) footnotes and endnotes can contain by nature various content such lists, tables, references, etc. which are, in the scope of a XML publishing workflow, subject to specific tagging. In other words, allowing tags in these contents is really a must have. Again in table cells - which are a specific object too, xml tagging is allowed.

That point plus the lack of management of mathml, is seriously blocking the use of InDesign in the scope of structured content workflow.
Which is a pity since in the meantime Framemaker - done for structured content - has itself serious lack in its rendering capabilities.

You can use the Find Text and Find Grep features to look for certain constant values, e.g 'point size 12 pts', 'tracking 75', 'space before 6 pts'.

But it's not possible to search for relative values, e.g. 'point size less than 12pts'. And it's not possible to do negative, e.g. search for certain text in paragraphs that do not have a certain paragraph style applied.

These features would make it much easier to find text with missing or incorrectly applied formatting, and generally would mean that the search scope can be specified more flexibly, which in turn means that InDesign's search feature would become even more powerful.

There have been feature requests for negative values (see links below), but not for relative values. I mention the other links here to consolidate these similar requests.

Find searches for anything that is NOT the term. eg. Find NOT 12 pt will select text that is not 12pt
https://indesign.uservoice.com/forums/601021-adobe-indesign-feature-requests/suggestions/39775783-find

Find all except this Paragraph or Character Style
https://indesign.uservoice.com/forums/601021-adobe-indesign-feature-requests/suggestions/30935179-find-all-except-this-paragraph-or-character-style

Find/Change "negatively" on a paragraph/character/object property (i.e., look for a style set to anything BUT 13pt)
https://indesign.uservoice.com/forums/601021-adobe-indesign-feature-requests/suggestions/34792552-find-change-negatively-on-a-paragraph-character

When working in a packaged file workflow, where Adobe Fonts are not and cannot used, if there is a missing font that a user might already have enabled in Adobe Fonts, InDesign makes a font replacement with no warning.

There is an alert to activate missing fonts, but no warning if missing fonts are already activated in the user's system. I’m not sure if you could limit this to: If there is a Document fonts folder present, then there should be an alert before fonts are replaced with Adobe Font versions. This should not effect if fonts are enabled in other font managers.

For example, if Scala Sans Bold (OTF) is missing from the Document fonts folder for a file, and the user happens to have Scala Sans Pro Bold enabled in Adobe Fonts before opening the file, InDesign just makes the replacement without warning. The user sees no missing fonts, packages the file, sends it to someone else without this font enabled, and the font is missing. This makes it difficult to maintain a strict package workflow.

This is critical for licensing when files may be worked on by outside vendors or freelancer not working solely in packaging workflows, where access to Adobe Fonts is not controlled.

I've been using InDesign in a Japanese environment and have long been frustrated by the lack of distinction between kanji and double-byte spaces.
When you want to select consecutive Kanji by double-clicking (or command + → etc.), adjacent double-byte spaces (0x3000) will be selected together.
When you receive an unsatisfactory text manuscript, double-clicking a wasted double-byte space will select the adjacent kanji together.
I can't imagine the single benefit of this specification. It's just inconvenient.
I would like you to improve this.
I hope you will get the approval of everyone. Thank you.

<Japanese>
私はInDesignを日本語環境で使用していて、漢字と全角スペースの区別がついていないことを長年不満に思っています。
ダブルクリック（あるいはcommand + →など）で連続した漢字を選択したいとき、隣接する全角スペース（0x3000）が一緒に選択されてしまう。
美しくないテキスト原稿を受け取ったとき、無駄な全角スペースをダブルクリックすると隣接する漢字まで一緒に選択されてしまう。
この仕様について、ただ1つのメリットも想像できません。ただ不便なだけです。
これを改善していただきたいです。
皆さまの賛同を得られれば幸いです。よろしくお願いします。

While hyphenation preferences can be refined at the Paragraph (style) level, Character (style) options only provide a boolean “No Break” attribute which prevents line breaks whatever the location of the text in the layout.

Note, for example, that “Hyphenate Across Column” is available as a paragraph option while the user may actually want to turn on/off column breaks from within a character style. The “No Break” attribute is then too harsh, since it fully disallows line breaking.

Suppose a ITEMS character style is associated to proper names or book titles. We may want to allow regular line breaking for these ITEMS within a frame or a page, but we may need to exclude breaks across frame or page, making sure that ITEMS always appear in full within a visual block.

A way to fix this would be to make the character “No Break” attribute more detailed. Instead of a true/false value, a dropdown list of distinct options could be implemented: [No Break (full), No Break Across Column, No Break Across Frame, No Break Across Page]

Note: The option “No hyphenation” (i.e. “No Word Break”) could be added in that list as well. This would address another feature request which is clearly connected to the present one: https://indesign.uservoice.com/forums/601021-adobe-indesign-feature-requests/suggestions/32293963-add-no-hyphenation-as-a-character-style

Thanks for considering this idea.

I don't think I'm asking for anything spectacular. I agree the Tabs interface isn't the best but, one thing that would make it much more tolerable would be, what I think, would be a simple change. Can we shift or ctrl click multiple tabs in the same section to slide all of them together please? Having to re-adjust all tabs on a line just because #1 or #2 need to shift to the right seems like a crazy oversight in functionality. Not to mention a time consuming and frustrating one. Please add this little thing to the next update and make a lot of us very happy!!