Conservative home has a helpful summary of the coalition deal. The greatest controversy thus far has surrounded the plan to raise the percentage of votes needed to call a general election. Rather than a bare majority, future parliaments would need 55 percent of the MP's votes. Here's Iain Martin:
[T]his fails the fairness test. It is an idea that has been easily and widely grasped for generations inside and outside parliament that if you lose a confidence vote by one then, there’s no way around it, you have lost. Fifty per cent plus one is enough. This seems such an obvious truth that one wonders why it was not apparent to the two parties negotiators that attempting to change the rules might make them look shifty .
Other dissents from Dizzy and Hopi Sen. Massie jumps in:
[U]nless I am hopelessly confused about all this, the provision has nothing to do with confidence votes. The government would still be brought down by losing a confidence motion on a simple majority. But, now that we have fixed-term parliaments, this wouldn't necessarily trigger a general election. That would only happen if it proved impossible to form a new government and, then, 55% of MPs voted in favour of dissolution and fresh elections.
This is a deeply tricky question - and I have to say my alarm bells go off. I can see how shifting to fixed terms helps this government, but constitutional band-aids for current circumstances, invented under extreme time pressure, have a real tendency to lead to unintended consequences. I'm going to think on this some more.