Labour's problem in this election wasn't so much about their policies, it was about the delivery of their policies. I don't honestly think many voters really disagreed with for example the Mansion Tax, the bankers bonus tax the abolition of the Bedroom Tax, the problem was that these things were the only things they talked about.
They didn't set out a vision for the country and where they wanted to take it in the long run. Yes they talked about how they'd help the working classes, but they did so without repudiating the failed policy of austerity. Also, they failed to even mention the middle classes during the campaign. They talked about the rich and the poor, not those who exist in between.
Consequently, though many middle class people may have agreed with Labour's policies, they didn't feel included in the overall project.
Looking forwards, I personally feel the best thing the Labour party can do is to not swing to the right drastically. They should appoint a new, young leader who actually comes across as leaderlike, and who talks about how the Labour Party will help both the working AND middle classes.
Unfortunately though, I feel they'll just elect a new version of Blair who'll drag them even closer to the Tories, and who'll fail to realise that it is possible to appeal to both the working and middle classes without losing the support of either.