Original sentence: Hare-Clark has been subsequently modified to allow for improvements, such as rotating ballot papers (the Robson Rotation).It is held up by its supporters as being the best and fairest electoral system in the world, but outstanding concerns remain that have prevented its widespread adoption
Edited sentence: Hare-Clark has been subsequently to allow for improvements, such as rotating ballot papers (the Robson Rotation).It is highly regarded as being the best and fairest electoral system in the world