Barring that though, if your party seems like it just isn't pulling the DPS it should, or they're too squishy, I'd take a look at those first. I had a mod that seriously increased not only the tactics slots I had per character, but also what you could do, so after a few trials and errors I had basically perfect setups on my chars.

I'd also pay serious attention to what tactics your party members are using.

Killing and/or weakening enemies before they get to you is definitely a sure-fire way to get past those more difficult parts. Leliana went with dual daggers, Sten used a 2h sword, and my character was a bow user. I made it through the game using only Leliana and.Sten? (Is there one more party member? FML It's been too long lol). I made it through NMM, without any 'cheats' of sorts, but I'm sure the mods I used gave me quite an advantage at some points. I'm addicted to installing mods to games like this lol. Unfortunately, I haven't played with a 'vanilla' copy of DA:O probably since it released.

Dragon age orzammar key to the city