I don’t really see the need for a “narrative lead.”
The only reason the ST has a chance of feeling like its narratively cohesive is that Abrams is returning. Had Trevorrow headed IX as was originally intended, it would have ended in disaster.
The canon is already a mess thanks to giving everyone free reign to take things wherever they want.
The GCW ends just a year after ROTJ thanks to Wendig, 30 years of potential were thrown out when Gray cemented that it was a solid period of peace and complacency. TFA is the very start of the new war and TLJ leaves no gap at all for anything in-between.
It would have been incredibly simple to work in room for expansion without affecting the narratives of either film but no one was there to guide it. It’s all a lopsided patchwork that will only get worse over time.