This would be a signal that political criticism and pressure on the court has had an effect. You need independence from the political process for the trial to work.
What's been important about the last couple of sessions in March is that there has been no major crisis, which is a change. It is beginning to look like a legal process.
This is a very important stage in the trial.
If the turnover of judges continues legal experts will begin to question the stability of the court.
Judicial positions are not musical chairs. There has to be some measure of consistency to be sure the trial has integrity.
There is rarely a smoking-gun evidence in cases like these. They may be beginning to move toward that, but to show the system behind the crime could mean going through thousands of documents.