She was like a superhero!
I liked Seven of Nine, and Jeri Ryan, too, and I don't even mind the fact she got a lot of screen time, but that aspect is sort of true, and was an issue for me. Need someone to go hand to hand with a wrestler? No problem, call Seven. Can't cure a strange disease? No problem, call Seven, and have her give you some of her nano probes to cure it. Got some weird space anomaly no one can figure out? No problem, call Seven. Need to escape from the Borg, pronto?
Seven just got too Mary Sue-ish after a while.