"The Local Government Boundary Commission for England is due to commence the electoral review of Sheffield in the summer of 2013. Sheffield was identified as one of the local authorities with an electoral imbalance... (...)
Alex Hinds
Review Assistant
Local Government Boundary Commission for England" (link)

A boundary review is triggered if more than 30% of wards deviate by more than 10% from the council average, or where one ward is out by 30%. As shown on this electorate variance map, Central is now 44% too big, and Burngreave and Darnall are tipping over 10% too big. All 26 other wards are within the required 10%, and most of them are within about 5%. Population forecasting shows a few other wards also creeping out of the 10% range. The review in 2013-2014 will result in all-up elections in 2016 restarting the four-year electoral cycle.

The review is now in Stage Two - drawing ward boundaries. Various submissions were made to the Commission on the council size (the number of wards and members). The Commission has deceided that there will be 28 ward each with three members, for a total council size of 84 members - the same as currently.

Sheffield City Council have been consulting to put together their recommendation for the ward boundaries,

I've put some initial data together as resources for people who want to put together a submission to the Boundary Review.

UPDATE
10-Jul-2014: draft1 and maps - draft submissions and maps. Will tidy this up as I work on it.

06-Apr-2014: CouncilSize.doc is my submission to the Commission on the size of the City Council (the number of wards).