Regarding collaboration, whereas we have two or three major parties, what happens then, of course, is more interest between parties. One important thing to bear in mind is that, for instance, we know from research that if you look at the coalitions that form, they tend to not cross the centre divide. What you'll see are left-wing coalitions or right-wing coalitions.
That means you have more representation of ideological values of voters within the legislature, and what that actually means for the co-operation within governments is that it now may be more likely to be coalition government if there's a change in electoral systems versus a single party government.
That might just have the similar level of co-operation to some extent with the big difference, though, that there's always a bargaining position between parties now rather than consensus building. If one party exits the coalition, the government will fall, and that sometimes creates, some argue, some stronger bargaining positions for a small party.