I get the problem. Wouldn't say it applies equally to other outlets. RT is very specifically a single-state propaganda tube, while a lot of Western press could perhaps be characterized as vaguely Atlanticist and pretty pro-globalization. But I'm not sure whether this was what you meant exactly by power centers.

Would they need more categories, then? Like geo-political orientation and state influence (although the latter would often be close to the press freedom rating)?

It looks like it, from the explanation of the ratings on the site. It would be impossible to consider the capitalist bastion of the New York Times to be left-leaning anywhere outside the Overton window of the United States.

Probably the same scale, although you can understand that in several ways. In any case, they clearly use the American typology, conflating the liberal-conservative axis with left-right. So it's next to impossible to tease out how left or right a publication is on more traditional markers, such as economic policy, in particular, but also labour issues, ideological orientation (e.g. Marxist/Social Democrat/Third Way/Social Liberal, or an even more mixed crowd on the right) etc.