I don't understand what you're saying here.
Why should SFWs get less out of Rationalism than Science-Focused Peaceniks?
I think it is reasonable that international cooperation gives a science bonus, but I don't see why Rationalism science bonuses should depend on international cooperation.
The Rationalism opener depends on international cooperation to ostensibly give an edge to tall, presumably peaceful civs.
First, I don't think warmongers have it particularly easy these days, and if they do it is probably because Honor ends up being very powerful, particularly the gold giveaways, which I think are much too high. You yourself have posted that you don't think conquest victories are particularly easy to achieve.
But second, even supposing that war was too powerful.... blocking them from benefiting from the Rationalism unlock seems like a bizarre way to nerf them.
I did post that conquest victories don't seem easier than others - but that's
with the existing Rationalism bonuses. That's why I don't want warmongers nerfed
further. Again, I agree that blocking warmongers from some of the potential Rationalism opener gains is not the ideal way to go about it.
I would say that the 5% system had huge balance problems, because I think that 80% science differentials are outside what I consider to be rough balance.
I can only base my opinion on the results of my own (many!) games. In those, the swing in turns is about 40 from fastest to slowest Science victories. That seems acceptable to me, although as I would prefer what Thal hopes to incorporate once he has access to the code.