Some time has passed since I’ve asked for feedback and there were quite a few responses on the PR and here in the Forum. There were some voices for most of the Options (stay as-is, revert to 0.3, runtime-dependant parsing), including for an option not included in my blog post: Basically Option A on steroids, where we expand the current behaviour to numbers (Option F).
If you’re interested in the individual arguments, I invite you to reread the discussion as I can’t fully reproduce everything here. But as a quick summary: The main argument in favor of Option B was predictability while the main argument in favor of Option A and F was terseness, primarily avoidance of additional parentheses, which can make equations harder to read.
There is no way to make everyone happy here, so it’s going to be a difficult decision either way. Personally, I believe that predictable, consistent, and intuitive syntax is more important than a bit of extra tersity (this is also in line with Typst’s generally design philosophy). While I wouldn’t say there is clear consensus, the majority of upvotes on both GitHub and in the Forum seem to share this sentiment. For this reason, I have decided to move forward with Option B.
Thanks to everybody who left feedback, in particular also those that argued for other options.