What a coincidence. I did that quest just last night and I don't think she finished off a single NPC. In the final room I killed everyone, the Skinner included and she was still battling it out with one of the Silverhands. I had to finish that one off too. So yeah, maybe with some good gear she'd more effective but without it the only thing she's probably good for is hunting elk.
OH EM GEE it's not just me then.
Do you want to know how I finished off about half of the hostiles in there, including the Skinner?
I had to engage their attention just long enough to make them want to chase me all the way back to the start of the dungeon, where you pull a chain and lower the spiked gate to get in. The first time I did that, I was just running for my life trying to find a place to let my health regenerate, or have time to "magic it back up" again if possible. I got all the way back and then realized I'd been followed, I pulled the chain and the gate went back up but the NPC got through. At least I was able to kill him without being attacked by any more NPCs at the same time, which got me to thinking. Because we were coming up on these baddies in groups of twos and threes at least, and my gear and archery are not good enough to guarantee a one shot stealth kill (altho I did get a couple, still a problem if there are more than two to begin with), and Aela was USELESS. She would engage for a fraction of a second before taking a knee and then I'd have multiple attackers on me and I'd... just... die. I had to use Battle Cry and a Storm Atronach scroll just to survive a third of the way through, and even that was after multiple attempts.
So anyway, after I remembered about the spiked gate and the dude chased me all the way back there, I had an idea, which was to just sneak up and put an arrow into the nearest baddie in the next group and then run like hell. Aela would go into combat mode and distract them all momentarily, and I could always get at least one to chase me. I would stay just far enough ahead (and not in Sneak) to keep them interested, then run like mad up the final set of steps, tear into the first chamber, and pull the chain. The gate would go up and the attacker would just stand there doing combat taunts and flailing at it with their weapon. And I would fire arrows into them between the spikes until they died. This took AGES.
I would finish them off, lower the gate, and head back down the dungeon, about halfway to where we left off Aela would come sauntering back to meet me, and we'd retrace our steps to wherever the last fight was. And then I'd repeat the process as needed until everyone in that area was dead, because not once while I was back in the first chamber shooting arrow after arrow into an enemy did she ever manage to kill any of them herself, until the end when I was able to one-shot a guy in the final chamber, then put an arrow into the second guy, then get the Skinner to chase me back to the gate where I killed him as described above. When I got back to the end, she had killed the guy that I wounded with my second arrow.
And it took me multiple attempts to get it to work for the final group of Silver Hand, the first few times I couldn't even run away fast enough to keep them all off me because Aela kept plowing into the chamber and blowing my cover before I could get a decent second shot off, then she'd take on 2-3 by herself and be down for the count almost immediately and I'd be toast.
Grrr. At least I think I'm done with the "forced follower" quests until I get Vilkas for the last Silver Hand mission, at least if he charges into a bunch of enemies he can do some decent damage in the process, not stand there firing crappy arrows from a crappy bow into them from two feet away while they're hacking you to bits.