Whether it's a mining ship or mining ship with a Borg skingraph, the torpedoes are all she seems to have. Whether to blow up asteroids or put craters in planetoids -- or to blow starships apart due to being filled with Borg slurm, it's what she has and uses.
They work, but they don't seem to be shielded to protect them from phaser fire -- a big flaw when you think about it.
The fleet at Vulcan probably died so easily due to not having their weapons fire directed at the torpedoes, as for all they know, they can't shoot them down (they can assume they're like torpedoes they're familiar with). The same with the Klingon armada -- they don't seem to rely on phasers either, so they'd be even worst off by just slinging photons, magnetic charges and disruptor bursts at Narada.
Enterprise figured it out (it's technically easier to shoot down something coming at you than it is crossing your path too).
I doubt they could have killed Narada though via conventional means. Even with Vengeance. Kelvin warping into her didn't, and that's a lot of energy.
After Enterprise showed how easy it is to shoot down the torps, you can bet any prior engagement will end in a stalemate, with Narada withdrawing due to being unable to get hits and the other vessels unable to fatally wound her.
Narada would need to upgrade her weapons -- probably by rejoining the Romulan Star Empire. Which would make her very powerful then -- she probably has more than enough power for Plasma Torpedoes and Cloaking from that era. A dozen plasma torp tubes would probably ruin the day for anything in that era, fleet or otherwise, in addition to throwing her standard missiles out to draw phaser fire.
Narada herself seemed far too durable for typical weapons of that era. I don't think Vengeance is anywhere close to the answer.