If two lanes are good Why not adding lane to make it three lanes. Right lane Right turn only, center lane for next turn going straight and left lane for going to the 3rd or 4th turn. course once you pass lane in the roundabout that lane becomes the right line. IMO that's the problem at couple spots too much traffic and not enough roundabout.
http://i1.ytimg.com/vi/k0H2URY7BX0/hqdefault.jpg