Proportional voting could strengthen democracy

Maybe. I suspect not. There are many ways to game such a system, and I don't believe it will resolve the underlying tensions that I believe are the core threat to democracy, at least in the United States.

(Namely, that we've got a deep antipathy and distrust for one another. Democracy is designed to give us a way to make collective decisions without having to make it personal, but the political is always personal and modern media makes it even more so.)

I'd be willing to give it a try. I think our preset state of affairs is so deeply problematic that pretty much anything different might give us an opportunity to find a better way of approaching each other.

But I believe we won't solve the interpersonal problem with any kind of procedural solution. We don't have to like each other, but we need to establish some minimum level of not actively hating each other, or we'll turn any system to each other's disadvantage.