Is there a commit size parameter for datapump import utility in the future? Currently there is none. I see direct path insert and parallel process are there and if so will adding commit size parameter help in faster data loading.
Commit size is not needed for DataPump because internally we're already optimizing performance of loading.
You're already correct in that the performance benefits will mainly come from parallel facilities.
If you'd like to really dig into all the performance best practices, here's an excellent set of slides from Daniel Overby Hansen
https://dohdatabase.com/wp-content/uploads/2023/06/2023_06_13_datapump.pdf which covers the fundamentals but also the various niche cases to be aware of (LOBs etc)