The root of the problem is our election process. It inevitably leads to a 2 party system. The fact that neither party truly represents a majority, is a large part of the reason why so many people are disinterested in politics.
A two party system prevents the need for unstable alliances, thereby giving the government the luxury of ruling for the fixed term without bothering about the need for finding additional support every now and then. I agree that one of the disadvantages is the exclusion of the smaller parties, but then every system has its own merits and demerits.