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.
Disaster because Trevorrow sucks, not because having another voice in the mix is inherently disastrous.
The canon is already a mess thanks to giving everyone free reign to take things wherever they want.
Well it depends on what kind of approach one prefers. Kennedy and the Story Group prefer letting creators have the freedom to tell their own stories in the best way they can without excessively worrying about and setting up other unwritten stories.
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.
Your supposedly canon-ending complaints seem arbitrary to me and narrow-minded. You’re talking about one specific era amongst many, and an era in which we’ve already gotten a decent variety of content (Aftermath, Bloodline, Poe comic, Phasma stories, Battlefront II campaign, Resistance show, etc.), with much more surely on the way (including The Mandalorian).