Interesting. If it were void shielded it might make sense to put all the eggs in one enormous basket like that, but if they can't make them for any water craft then it seems more sensible to distribute stuff more like we do today.
Imperium is always in big things. Big tanks, Big ships, Big airships ... in our "modern" view there is not much sens in Baneblade or Stromlord super heavy tanks. But they are bulid to last, intimidate and ride with heavy firepower to overrun everything. The same thing is with Imperial ships ... they dominate, If you fight hordes of orks you don't need fleet of "modern" destroyers ... you need something like
Argo Nautical, something with such level of firepower it can level whole islands with it guns and sends wave after wave of fighters and bombers.
You just need to think realy BIG!