I'm currently approaching 6 stars on Sid,GS, and Lumi. I'm getting QGJ from cantina shipments.
Chewie at four stars rounds out the team. Chewie sucks but at least until 6 it didn't seam advantageous to delay improving my other main guys.
So do I finish off Sid, Lumi, and GS or at six switch one. My gut says the jump from 6 to 7 is less that the jump by replacing 4 star Chewie with four star someone else.
The next question is who. Leaning toward Phasma out of GW as it will be the fastest to make an impact but really open to other ideas.