I think that was the point. The fenris has never really been that strong. It was supposed to be more of a Knife Fight weapon me thinks, like for taking out freighters and .. tickling other cruisers. About the insignificance, that just shows how much the shivans own

The SGreen itself is also rather weak, but I think it kinda suits the type of ships that use it.
What I think was an actual error was the Mentu's loadout. I think it was meant to have to SVas's. it says so in the tech description and it would make sense. It would make it the perfect ship to take on the convoy escort role that the terrans have with the Aeolus.
Another obvious and well known error is the Mjolnir, which in the Tech description has 2 missle launchers along with the main beam i think. Personally, I think it is balanced fine right now for what it is as a first generation RBC. If it were to be beefed up without changing the design or model, I think it should have shields.
I think what would be cool is if the Lterslash was turned into a sorta Ultra AAAF for caps. the UAAAF actually does more damage per minute than the LTerSlash and possible SGreen although I can't remember (it's on Zylon's FAQ). But maybe making the Lterslash into a long range rapid fire, kinda weak beam, against cap ships, maybe using it to disarm ships turrets and so on.