When the Fixed Term Parliaments Act was debated, Labour was pretty insistent on it being fixed to four years, not five. So, what if it had been? Suppose the Lib Dems insisted on it and somehow got their own way. Would the results of the 2014 general election have been enormously different from what they would have been one year later? I'd predict largely the same results for UKIP and the Lib Dems; the latter had already bottomed out by 2014, the European elections proved that. But for Labour and the Tories it's more difficult. There were the first whispers of an improving economy but would it have been going on long enough to seriously sway voters? And could Labour win much more support after only four years in opposition? And of course, the Scottish referendum hadn't yet happened so we likely wouldn't see any SNP landslide. So here's my personal prediction for the 2014 election:
Conservative: 284
Labour: 270
Liberal Democrat: 11
Scottish National: 7
UKIP: 2
Green: 1