The point is that a proportional voting system would be more democratic overall. There would still be a right and left wing split but it would allow for many more parties with differing perspectives to exist within it.

Coalitions are always a possibility but I’d rather have two left and right wing coalitions made up of 5+ parties than a two party system as coalitions are less likely to be as unified. Also more diversity probably reduces corruption and regional grassroots movements may have an easier path towards attaining political power.

And like you said, such a change wouldn’t prevent fascism from taking hold either. Fascism never respects democracy and as such it cannot be dealt with by changing our voting systems. Rather, I believe the best way to deal with it is to explicitely ban it by law, paradox of intolerance style. In other words, you shouldnt be able to vote for someone who doesn’t believe in voting or in democracy. Also education is very important in this matter like you said.