Sure, and that's exactly what they did. By waiting for him to come out once Ecuador dropped terminated their asylum. It absolutely matters in that they would be violating Ecuadorian sovereignty by doing anything but waiting for something like this to happen.
> But DOJ didn't wait until Ecuador dropped the asylum.
Well that's just flat out false. Here Moreno (Ecuador's president) says: "Ecuador sovereignly has decided to terminate the diplomatic asylum granted to Mr. Assange in 2012." https://www.youtube.com/watch?v=tHVqbKgsnDw
> There was nothing preventing the indictment, there were circumstances that would prevent unsealing the indictment.
I get your point about filing and then unsealing but that's just mincing words. You can disagree with process but I don't think that makes it "political". I don't pretend to know why prosecutors decide when to file anything and I think you need to bring some proof that this would be improper if you are going to assert some wrongdoing here.