I ride an old '07 Roubaix, and it's my go to bike for lots of rides, centuries, even club rides where I just want a comfortable bike for recovery rides. The new Roubaix are light years ahead of mine. As for the new Roubaix, several club members have the new ones, Di2, hydro disc, new compliant suspension tweaks, and love them. How much more stuff do you need? As for Domane, our ride leader just moved from a couple year old Domane to a new Roubaix, and he loves his.
My old Roubaix near the top of Gibraltar Road climb