I just did Rator Prime in my Neb: Cmdr 2 and the Decius at the end is now a butt-kicker. It decimated the entire first wave of defenders and it ended up with me and a Galaxy fighting him alone. Then a second wave of Feds showed up and we had to lead the Decius to them. That was a hugely tough battle; especially with the Decius now cloaking in and out. I'm going to have to retry it with another ship as I don't know if that was a Neb fluke or if they really made the Decius that much more powerful now.
If the Galaxy was a player that was not adjusted to your level via the buddy system then the NPCs would have adapted to fight him and thus would have jumped up 30 levels in power, allowing it to annihilate everything you level in it's path.
It was an NPC. The Decius wiped out everything, including the San Jose. This was my 10th time doing the mission and I've never seen the entire fleet destroyed before: but I never noticed the Decius using battle cloak before either. I'm just glad the second fleet arrived. We only had it down to around 40% and things weren't going well.
I don't know if it's just the slowness of the T3 Nebula or if the ship's been upgraded in ways other then the battle cloak since the last time I did it.