We have nothing against "big bad ships". Inferno already introduced one of them in form of Vidyadhar superdestroyer. Gigas is likely to appear, but it won't be just ridiculously large warship designed to engage enemy fleets. It's sheer size must have some point, but being just a giant warships for being giant warship is wasting resources for something, that is in turn also logistics nightmare. Gigas is already shortened from 22 to about 11km. It's real purpose, probably associated with some strange, subspace magic is being debated inside our team.
As for Icanus, this thing is ridiculous especially for terran usage. As we slowly rework EA from "generic space nazist" faction to more intelligent and cunning enemy, we also drop ridiculous things. EA proved that they can build smaller warships [Nemesis] capable of engaging much larger targets, like Sathanas. They really don't need such a thing. Instead they can maintain balanced fleet of high tonnage, full of specialized capitalship designs and easily roll out new forces to the frontline as situation change.