I’m not sold on two Death Stars to start with. The second being bigger and badder is enough of a threat. Starkiller would raise lots of questions like why the rebels never went after it or the empire never used it in the years prior to Force Awakens or why anyone is surprised by it.
I’d also highly recommend trying to implement even just one or two of your proposed changes as a proof of concept video. The brainstorming is fun, but you’ll get better feedback if you have something you can point to that shows people you can actually make it.