In order for LEAN pull planning to deliver any benefit to a team it must link back to the project schedule and critical path. I would think a direct link (live sync) or an import/upload option for users to bring in a master schedule from P6 (.xer) or Microsoft Project (.mpp) would be sufficient to bring in a WBS along with activity IDs and start/end dates for early, late, planned, and actual.
Has there been any progress in this space? Your leading competitor has had a schedule integration for linking to other entities (submittals, RFIs, etc) for some time now and Oracle Prime has the ability to link to a live project schedule as well.