On Sheldonbrown.com,, he recommends having the brake cable anchored,, when wrapping aero bars, and taping the housing first to the bare bar. I think it does make a difference.Otherwise you have a soft,,sluggish feel with the levers.
If the cable housings are a tad too short,,when turning the bars left & right,,will also degrade the braking feel. Could check how the calipers engage,, a dragging pad.Chris