Participation requirement isn't the biggest issue with the ITTF ranking, the bigger issue is their weighting system of the points. The earlier rounds are getting too much points in relative of the winner or finalist. It is obvious when compared to ATP tennis.
http://www.stevegtennis.com/atp-tennis-ranking-points/
A tournament winner gets only twice the points of a first round loser in an ITTF World Tour event. Theoretically two first round defeats are as good as a tournament win which is really bizarre, this is a huge difference to ATP tennis.
Another issue is the players limitation for the world championship (4 players) and Olympics (2 players) from the same country. Lots of really good players from China or Japan are not even allowed to participate. Even for World Tour tournaments there is a limit for players from one country.
What happened in the screenshot in the first posting? Ma Long only with 1350 points?