The Specialiaed Roubaix is the best endurance racing bike in the world. I had to laugh when you wrote it didn't feel so good. I have owned 50 road bikes and the Roubaix feels the best and is taylor made for guys like you...and probably the vast majority that ride but instead choose a less comfortable bike.
Racing bikes tend to put a fair amount of weight on the wrists. Yes position is key to mitigate this but there is no substitute for a higher handlebar which btw will make the drops much more usable.
The twitchy steering you also write about the CAAD 10 is similar to many other race bikes. The Roubaix by contrast is rock steady. This maybe the 'feel' issue you have the Roubaix. Having owned many short wheelbase low trail quick handling bikes...the average rider will have greater control with a Roubaix because it tracks like a slot car.
Good luck in your recovery.