There's no actual proof it'll lead to the third war against the Empire (though I agree it's somewhat likely), especially as it's also been said that you won't be forced to do all the 3.x story to get to 4.x content, so any foreshadowing in 3.x is not necessarily proof. After all, you won't need to get that foreshadowing to get to 4.x, so... ^^; It's a bit like having two spin-offs from one series, and saying "well, in spin-off A, it totally foreshadows this thing happening, especially close to the end of it, so we already know it's going to happen in spin-off B, even though they theoretically take place at the same time and thus can't really be foreshadowed like that".