Thank you for your feedback! Pivot table creation is in our backlog. Once the dependencies needed to implement this are in place, we’ll begin the implementation.
As always, when the design draft is ready, we’ll present design for your review under the open-spec branches of repository: https://github.com/officedev/office-js-docs.
Office Extensibility Team
You have to give this functinality as soon as possible it is very fantastic .... waiting for this feature.