You can't just decide that A) the folks who didn't vote would actually vote for your side and B) that turnout would be significantly higher (Italy's last election had about the same turnout, Austria had higher, both turned out governments of which you would not approve.)
I'm opposing this system because it has turned out really bad results in the last decade and I care about the people those governments would hurt here.
You might be okay regardless of government, I care about the people who wouldn't be.