I would agree with @Ben Rowny here. At my last client and now with my current company, we are planning to utilize the LOA table and extend the leave types even further. I'm planning to make use of that table instead of creating "leave start" and "end dates" (and what not) on the LE Case Table (or any other Case table).

Furthermore, I don't think that ServiceNow has ever mentioned that they plan to "further update" the exmployee experience packs - even if they give you a good starting point.