I know that it would be a better design, but then Intersects would be the only non-member function of sf::Rect (out of two ) and even of the whole SFML API. Weird.
So I think that I'll keep it as a member, for simplicity and consistency.
That's a good point. Now that you say it, I see that there are hardly global functions in SFML (apart from sf::Sleep(), the vector operators and maybe a few others). So you're probably right.
As far as I remember, Doxygen also has problems with global member functions. In order to list them together with the class interface, you would have to write modules and group functionality. For example, sf::Sleep() currently doesn't appear in the documentation.
Another question: Why are Rect::Offset() and Rect::GetCenter() no longer necessary? Now, one has to write
MyRect.Top += OffsetVector.x;
MyRect.Left += OffsetVector.y;
and
sf::Vector2f(MyRect.Left + MyRect.Width/2.f, MyRect.Top + MyRect.Height/2.f);
to achieve the same. It may be fewer work than with Right/Bottom, but it's still quite tedious...