In several applications/operating systems with multi-paragraph text fields, the direction of each paragraph (=line-break-separated stretch) of text is determined by the _contexts_ of that paragraph. Typically (but not always) the first strong-directionality character of the paragraph sets its direction. This should be supported in LibreOffice - as another option in addition to LTR, RTL and "Use superordinate object dir". It allows users to avoid having to explicitly set directions back and forth when switching from one paragraph to the next. It would be particularly useful in Calc cells and single-paragraph Draw/Impress objects. Also, I think MS Office has this, at least in Excel cells.
(In reply to Eyal Rozenberg from comment #0) > Also, I think MS Office has this, at least in Excel cells. Yes: https://support.microsoft.com/en-us/office/change-the-alignment-of-text-in-a-cell-6426fdc3-e0da-41f9-bfe1-82f064a9696c#bkmk_rtl So in this regard, it would be an interoperability issue.
Reasonable, assume ICU libs would support it already in some fashion--at least the directionality. At minimal performance cost--edit engine(s) during user input only? RTL / LTR should then be retained in ODF, so not reparsing on import?