Terminator:
I find puzzling all the excitement over this decision. What I found most interesting were the pointed messages to the AU, politicians, and others who have been keen to interfere with judicial processes. To the extent that you are interested in anything else, I suggest you skip its details and consider the mere fact that it's been made and the implications as to what is coming next. For that, you should look at the OTP's original application to get the testimony in. The OTP asked for the application on Rule 68 or, in the alternative, Article 69 of the Rome Statute; the Trial Chamber went with the former. The OTP will now go back---and very soon, I believe---to ask that the evidence to come in via the latter.
Article 69 allows the judges to admit into evidence anything they think will help uncover the truth. In this case, although the judges in the Trial Chamber disagreed on the initial ruling, they all agreed that the evidence should go in on that basis. So it will go in, unaffected by this Appeals-Chamber decision; what's more, the Appeals Chamber will be very reluctant to interfere with an Article 69 decision.