First, it had 5 weak points.
Second, the Shivans managed to fail at killing all the Vesudans.
Third, it would be a massive success over not having any answer to the question of what the hell we're doing here.
Personally, I keep hearing people go the nanite route with who they think is chasing the Vasari. Since the first scene we see is the Vasari unlocking phase space and they have such advances on said tech, I would think that they maybe pissed off somebody with their phase manipulation. And I'm not talking that inter-dimension, stolen from Start Trek: Voyager crap. I'm talking someone who was badass in their own right and then got screwed into phased obscurity via this technological breakthrough. Someone who not only learned to break the bonds of phase space in order to return, but even learned to use it as a weapon so that they could apply tactics that would indeed drive their opponents insane. I already have an en media res scene in my head that would serve as something of a treatment, but I've found it thus far pointless to write.