I would beg to differ that the issues pointed out with React are caused by JS. Lit offers reactivity like React but uses native JS objects and not artificial callbacks and such. Thus, you can pass whatever objects you like, independent of the functions that use them. Lit doesn't render again unless the actual referenced object changes.
Structural-equality for arrays, objects, and function-closures by-default would be a performance... improvement? Might want to check that math, hoss.