What some call twitchy I call sporty. And I like sporty.
Not all really lightweight bikes will feel twitchy or sporty. Also, if you ride long or do happen to have some hills of 5% grade there in Chicago, a 17 lb bike will make those short hills disappear. And you'll have more energy left at the end of your ride for that sprint to whatever your personal finish line is.
If you truly only ride on level terrain or only ride for 75 minutes or so, then weight is not so much of an issue