in the long-run, it will still go back to majorities of party and will gonna narrow to 2 major parties clashing.
I'm not sure it will. In a two-party system, Party A is always going to attack Party B, because they need to take votes off Party B to get seats off Party B. But in a PR election, lots of parties get seats, everyone has their own angle, and it's no longer a case of forcing everyone in your party to band together to attack the opposition.
And even if PR does result in two parties getting all the seats, then that will be because those two parties got all the votes... which is a lot fairer than it is now.
But two party system is just a concept of two major parties in the government. There are other minor parties but it just happens that these two holds too many peoples, thus having major power in politics.