I only played in 8.1, but the rakia was by far the most annoying ship i have ever met.
I was doing the gladiator bounty where it appear and I had to restart several time. This thing was not catchable, I would wipe the entire fleet and it would escape, barely damaged. I did not have tons of fighter mind you. And I managed to destroy it once I bought and equipped several dedicated fast carrier with decent speed fighter.
Nevertheless, I do not think it was intended to be a normal occurrence, so I guess its fine if it's a bit op.