The recent improvement in querying attributes makes really easy to pull together semi-structured data. Schedules and deadlines are arbitrary keywords in the block and it’s not possible to make tables or process them like anything else.
I think it would be better to embrace attributes as much as possible and move schedules/deadlines to attributes. It would make data processing easier.
Not sure about the implementational details, so the following is just a possibility:
adding it as namespace attribute:
logseq/scheduled:: [[DATE]]
This would break org-mode compatibility, so it must behind a feature toggle. (Not sure how many of the users use org-mode with Logseq)