Sounds to me like the Domane is the way to go. Your description of the Roubaix's smoothed out feel from shock absorbers, is probably also the reason you don't feel "in" the bike. It's like the proverbial cadillac floating down the highway vs. something tighter like a BMW or such. One feels great.. the other connects you to the road more.

Also fwiw, both bikes are not equivalently 105 drivetrains. The Spesh has after-market chain (KMC), Crank (Praxis), and Brakeset (Tektro).. I've never understood the frankensteining approach when these guys spec their bikes.