There will be more code-sharing. There will likely be FF reciprocity. B6 might even try to join *A at some point. And that's about it. T5 has no USICS services so they can't handle international arrivals and there is no lounge available for LH premium passenger on a departure. Plus thee gate areas can't handle wide-body loads. And, on top of it all, LH owns part of T1 and they have made major capital investments there. They aren't moving.
Nothing is going to change.