My opinions from what little I know of the time:
- Egypt be like: "Ah shit here we go again". How do you say that with hierogliphs?
- There will be a third intermediary period full of infight between multiple competing dinasties of foreigner and local kings. Either might come on top. Its Hyksos 2: It Came From The Sea
- Possibility: A Kushite conquest of Egypt? Or Kush could fall after that.
- What allowed the ascenssion of Assyria was the Bronze Age Collapse. Egypt managed to tank it out, then fell for a while, while Assyria lost land but survived whole.
- The fall of Assyria means even more dominoes falling. Perhaps we get "Sea Peoples" and Assyrian dominoes falling as far as proto-Persia.
- A good question is: Will the Kassites/Babylonians manage to ride out the devastation of Assyria, or will they fall??
- Hebrews are already around
- Mitanni already conquered, aren't they?
Anyway, I think that a fall of Egypt + Assyria means pretty much a blank slate in the region. I think the new potential players in the region are:
- Kassites, IF they don't get ravaged after the fall of Assyria
- Mitanni, if they manage to become independent somehow
- Urartu, if they are not conquered by Assyria or its sucessors during the time
- Phyrigians
- Hebrews, who are now more or less g etting themselves together