What I thought was that the Liberal Democrats were being incredibly naive and accepting an empty formality when they should have insisted on a real concession. Nick Clegg said that AV was a major sticking point when negotiating with Labour. Well look at what the Tories gave him in the end, nothing.
Erm, any sort of voting reform was always going to involve a referendum, regardless of party putting it forwards. The Conservatives have always been against any form of reform (common wisdom has them losing out badly under any preferential or proportional system) so getting a referendum from them was a major concession.
In the end the referendum came to nothing, although a lot of that is still on Labour failing to support the vote (it's been in their manifesto since 2001, then comes up and they have no official position... while their members came up with some of the nastiest lies in the No campaign) and the overall anger at the Lib Dems for joining the coalition. They did still get substantial electoral reform in the same bill, which looks like it may go even further this year.
Now I know a few Green activists and members who felt that the Lib Dems were 'selling out' too cheaply and should have held out for a STV law. But that both assumes that such a thing was ever going to happen (no party proposed any reform without referendum, and STV would have been an even harder sell, completely restructuring the Parliamentary constituency system) and that the Lib Dems were selling out. That completely misreads the party of 2010, assuming they were somehow closer ideological and politically to Labour (and especially Labour under Brown) and that going with the Tories instead was a greater compromise.