It might not be that much more powerful than other endgame abilities, but it is better than everything up until endgame. You could get a multitude of stabilizers and the tech near the beginning of the game when everyone else can't even research ships that stand a chance. While everyone else has to extensively research and build economy in order to build a substantial fleet, the Vasari only need an extremely small economy and one line of research to build and sustain a more than substantial fleet. It is literally impossible to counter unless you can kill the person going for it before they attain it. After it gets started, the only way to counter it is if you team up against the person with it and it would still be hard to win.
Erm, I have to disagree. Returning Armada is a long way from being an 'I win' button.
The costs to get to Returning Armada and build enough phase stabilisers to make it useful are pretty steep, and to do it quickly requires a powerful economy, which puts you in a position where you need to save every credit and resource for research and building stabilisers, but also need to expand rapidly.
I'm not saying it isn't powerful, but I don't think it's over-powered, and nor do I think that rushing to it is the only viable strategy for the Vasari.
