I agree. This sounds like a set up for the sequel trilogy. I guess we've got a first hint of who the main antagonist would be, this new Emperor. There's even a not so subtle hint that the ToM would play a role. Brandon has also hinted post-ToG that the Seanchan cycle of prophecies would play a role in the sequels (in the sense that he answered a question about it by saying if the sequels are ever written, we'd learn quite more about the cycle)

I think we're probably to expect more specific hints before the end. I think Brandon and Harriet are genuinely uncertain whether they should and will have the sequels written. If they decide against it, those clues will become Fortuona's open ended "epilogue". We'll never get to see how she deals with all this, but at least we'll get some idea of what challenge awaits her and Mat on the other side of the ocean.