Thanks for the compliments! To answer some questions, it is based on the Fenris hull, but with some significant changes to accommodate a different role. It is also larger, but not as much as the radar dishes may lead you to believe - the dishes are smaller than their Fenris equivalent.
The hole in the middle - nope, not a fighter bay. It's multi-purpose - it CAN carry cargo, shuttles, etc, but it's main role is to carry and launch a specially designed bomb intended to collapse subspace nodes. Orions are a bit more expensive than a purpose-built bomb after all, and all that was needed after the bomb was developed was a platform to deliver it to it's targets.
Backstory-wise, the reason it was based on the Fenris was not so much anything to do with the Fenris itself, but rather the fact that there was already the infrastructure in place to manufacture them or Leviathans in fairly large quantities. So this was supposed to be constructed with as many repurposed parts as possible, rather than requiring a whole bunch of new R&D, infrastructure, etc, before the ship could be built. Essentially, it was urgent to get it constructed, so anything they could do to reduce the initial development costs and then the price-per-ship was pretty important.