What is clearly the advantage in my mind for the 125/125/berzerker is that it allows you to think more about other things with your research. It compensates for small deficencies in sensor tech, weapons and ship size. It allows you to not be completely dedicated to getting your ships trained to the limit right away.
While the race that is behind in these areas must be extremely diligent in making sure that they do not fall behind in anything or it will turn the battles that would be draws or grinding battles of attrition into outright routs.
It's kind of ironic because the race setup as the warlike one can relax and think about trade and politcs, while the race setup to be a trader must concentrate heavily on warlike R&D.
But it's not unbalancing IMHO. Not gamey. Just part of the game. Part of the risk reward that you have to consider when setting up your empire.
Geoschmo