You put those words very well. This was exactly what I was trying to express. But due to my limited technial knowledge couldn't do so
That summarises most of my feeling.
Xu xin and Jun Mizutani can't be assessed with normal standards.
That was a very subtle observation. I too was explaining this to my friend that zJK extend his arm fully sometimes like xU Xin while looping and driving. He has a complete unique FH skill set. Sometimes, smaller movements. In case of choppers, longer arm extension. He also does it to increase power near the table. This also explains his incredible forehand flicks, to externd FH in forward direction.
Timo Boll also subtly changes the length and size of his movement but not as much as others given his focus on spin. He is predominantly a spin player and developed his style in the era of the 38mm ball. The feature of his style that translated to the 40mm ball era was the close to the table play and consistency. The larger ball hurt his spin.
The thing is that there is significant diversity in European countries for style of play and technique. While there is diversity on the CNT, my sense is that certain things are also discouraged if you don't fit into a certain mould (players who finish their stroke as far across the body as Boll, Maze and Mizutani would probably draw some funny stares from coaches at the Provincial level and would not even be allowed to try out for CNT unless they beat everyone 11-0 - you get my drift).
In any case, technique is something you develop in youth and winning is what it is - at this point, you should just celebrate Boll for what he is. While you may think otherwise, in terms of strengths, both Boll's and Mizutani's forehands are their strengths in terms of rally play, as much as they both have decent BH loops. IMO, Boll's looping technique is fine, but he is unable to counterattack aggressively with his backhand close to the table so the Chinese feel safe looping to his backhand as he needs to pivot to get a strong counterattack and that opens up the table. When you compare this to Ma Long or Zhang Jike who will just give you more resistance with fast blocks and counterloops at the table, you can see what Boll's real issue is.
His consistency and spin more than make up for any technical deficiencies. It's the inability to counterattack very aggressively on the BH vs. CNT level pace that is the issue.