Agreed!
Jun Mizutani has a great shot I think.
He has had some decent matches lately, but every time I have seen him play in last couple of years, he just seems too passive (not aggressive enough) to win against top 10 players. All too often within first three balls of a rally he starts moving backwards and ends up in a lob-fest. Fun to watch, but you can only expect to win about 1 in 5 of those rallies if you are the one defending against a top player.
Samsonov is in a similar category unfortunately. In Men's World Cup last year he played very aggressive against Boll in first two sets and went 2-0 up, but then reverted to his usual counter-attacking / absorbing pressure style and let Boll dictate the pace and lost 4-0. Perhaps due to tiredness, but he should he can do it against Zhang Jike in Euro-Asia.
If only Mizutani and Samsonov could maintain that level of aggressiveness they could win against the top players, but without it, they will certainly lose to the first or second Top 10 player they come up against.