The one important concession made to the Liberal Democrats in the coalition agreement was a referendum on voting reform in May. If it is lost then the issue will be dead for a generation. But the Coalition is itself the greatest obstacle to winning it.
A new voting system would make it virtually impossible for any party to get a mojority in Parliament. In other words it would be the beginning of an era of coalition governments, and after the current experience coalition is going to have a bad name. To make things worse, the Tories will campaign against reform, and so may many Labour supporters, leaving the unpopular Lib-Dems the main campaigners.
What we need in addition to voting reform is a system that prevents politicians from ditching their policies for the sake of seats in Cabinet. It should be possible for voters to censure their members of Parliament. For example, it might be made mandatory to hold a rerun of the election, if more than say 10 or 15% of electors in a constituency sign a request. The same system could deter members from fiddling their expenses.