Some reforms would result in entire changes in the party system itself. Regardless of the reform, parties will adapt their behaviour to reflect the system and the outcomes they think they want to pursue. It's not simply the question, “if the 2015 had been held under system X, what would have happened?“ That's a simplistic way to go about it, and it's not very compelling, in my view.
On August 23rd, 2016. See this statement in context.