I think a few things factor in on this feeling. First of all, the French crowd has always been pretty nonchalant at RG. Very infrequently, they get behind the players and root for them (even their countrymen).
Secondly, this year the temps have been cool and rainy; the roof would improve the tournament and the crowd experience. Use it.
Thirdly, it's every guy against Nadal. He's the greatest clay courter ever, so every other ATP player is out there for table scraps.
Fourthly, the WTA is totally inconsistent. We see a lot of 6-0, 1-6, 6-2 scorelines, it's not close and lacks drama.
Fifthly, it's really hard to see the ball on TV during play. It kind of gets lost in the shadows so it's hard to follow (similar at Wimbledon during second week).