Compare that to the first-past-the-post systems of the UK and US, where there are essentially no minor parties with any hope of having a say.
Also known as the 'choose between two dictators every couple of years' style of democracy.
That's not even taking into account the influence tiny parties can have merely by virtue of having a seat at the table and engaging in the discussions.
[1] http://en.wikipedia.org/wiki/Party_for_Freedom [2] http://www.powned.tv/nieuws/politiek/2013/08/peiling_coaliti...
Obviously, the mechanics are different (and, IMO, more colourful) in a multi-party system, but at the end of the day, Wilders can only decide to support Rutte as PM or, after applying the full might of his party, not supporting Rutte, who, never the less, remains PM.
They are probably an important factor in shaping public debate, and thus, shaping general policy, but you don't need to be a member of parliament to do that and plenty of non-MPs in FPTP and PR systems alike do just that.
In general, simplifying the situation, PR-systems simply give the population more degrees of freedom in steering the government.
Even though it's still just a handful of options over a single binary choice I'd argue that this difference is not inconsequential.
My usual argument against FPTP is that it's much harder for the population to challenge the two dominant parties in case they choose to collude (or more precisely: impossible to challenge the degree to which they collude) which seems to be the failure mode the US democracy is currently experiencing.
But instead of arguing over the Tea Party: How has Wilders caused the dominant parties in the Netherlands to collude less than the ruling parties in the US and the UK?
Basically, my thesis is that parties are mostly irrelevant. If there are important wishes in the population at large (ie. showing up significantly in polls), those will mostly be accommodated, not because of ideology, but because of self-preservation. For the 99% of stuff that we don't hear and care about in our day-to-day lives, the bureaucracy is in charge in all important aspects, and the iron law of bureaucracy[1] applies supreme.
It is a dangerous distraction that changing the voting system actually changes anything that matters.
1: http://en.wikipedia.org/wiki/Jerry_Pournelle#Iron_Law_of_Bur...
As for Wilders, you could say that the dominant parties were all colluding on treating low-wage earning immigrants the same as low-wage earning Dutchmen. As painful as it is, Wilders did result in changing that.
As for the dangerous distraction, that could well be true.
I like IRV in that it gives voters a greater say over who finally gets elected (though it can often lead to the surprise selection of the least unpopular candidate, to the consternation of the electorate - see Oakland, CA) but I am no convinced it makes politics and governance better automatically.