I don't know what book you are talking about here, but the SWTOR graphic novel "the lost suns" classifies Ascendant spear as "long range battle cruiser with class 0.5 hyperdrive". Whereas the silencer is a rapid-recharge fleet-killer megalaser. I don't know what would make Asc. spear as the particular ship of destroying rep fleets..
Also, I think the fate of the silencer is reserved for Bioware. I HOPE I will get to see it again ingame and preferably not in ruins (my main character is an inquisitor). I guess all other people creating SWTOR -related stuff out of the game are told to keep their hands off the silencer.. I just hope Bioware gets to writing episode 4 for all of our characters one beautiful day..
Ascendant Spear, in Annihilation was a cruiser made of special technology, the Sith could link with the ship through the Dark Side of the Force and command every piece of it like controlling their own body. And it was capable to destroy fleets.