Quote:
I can hardly imagine that there is a world-class player who wins more than 50% of the matches at the highest gnu level. But that too is only a subjective assessment.
This is not even close. A top world class player wouldn't win much more than 45% of 7-points matches on average.
It is not subjective either : the play of gnubg (or XG which is even slightly stronger) and of the top players have been abundantly analyzed, their average error rates can be computed and from that it is possible to estimate winning chances depending of the match lengths.