While that wouldn't be bad, I don't think Disney will be able to do that - Kennedy is well established with decades of hit producer credits behind her, and I would imagine her contract would be bulletproof
Firing/sidelining her would PR very badly and make it look like Star Wars is falling apart, prompting media calls of "has Star Wars become the next DCEU" etc - the headlines practically write themselves
Johnson on the other hand might, one year down the line, find his own trilogy perpetually in contract limbo