Why the field becomes the weakest since 2015? Look at the ITTF winning % of more people, Wang Liqin, Ma Lin, Wang Hao, Zhang Jike, Xu Xin in addition to Ma Long (they are the highest, outside CNT, Timo Boll may be the highest). Look at 2008-2014, the field does not seem stronger than afterwards. Don't tell me Ma Lin and Wang Hao's good days were gone in 2008-2009 when the former got OG gold and the latter got WTTC gold and National Games gold. And don't tell me the dominance of CNT was not challenged in recent years when more and more non-CNT players other than Timo Boll and Dimitrij Ovtcharov improve and beat CNT.
Some arguments are about younger players missed the prime time of senior players. This may be partially true because the quotas were limited for CNT to send players to international tournaments (OG 2-3, WTTC 5-7, WC 2-3, world tour 6 previously). But there is no such limitation at China National Games (every 4 year), which is said to be the most competitive TT event in the world, with Liu Guoliang's best result R16 out of 3 attempts and Zhang Jike's best result 7th place out of 4 attempts.
2001 gold: Ma Lin, silver: Qin Zhijian, bronze: Wang Liqin, 4th place: Kong Linghui (his best result out of 4 attempts)
2005 gold: Wang Liqin, silver: Wang Hao, bronze: Ma Long, 4th place: Wang Liqin
2009 gold: Wang Hao, silver: Ma Long, bronze: Wang Liqin, 4th place: Xu Xin
2013 gold: Ma Long, silver: Fan Zhendong, bronze: Xu Xin, 4th place: Wang Hao
2017 gold: Ma Long, silver: Fan Zhendong, bronze: Wang Chuqin, 4th place: Xu Xin (semifianl WO)
Not considering the winning % and head-to-head, I think there is no room for argument who is the best Chinese player ever because only Ma Long wins Grand Slam AND China National Games (the other three Chinese Grand Slam winners did not get a single medal; other China National Games winners did not complete Grand Slam). But of course fans have interesting thoughts. Give you two examples (HT to Zhang Jike fans on Chinese weibo): Ma Long's 3 WTTC titles are the weakest because he never faced a former WTTC champion in the finals. Ma Long's OG title is the weakest because nobody did not drop a set in the OG final!
The choice for the best player ever, is simple, Jan-Ove Waldner or Ma Long. Ma Long was asked this question in Liebherr Live, but unfortunately the interpreter mistranslated into who is the currently best. What does Ma Long think of Waldner? He was asked by Spin College during 2019 WTTC and said, "Waldner is a legend"; in Liebherr Live, he said, "The strongest feeling (after winning the third title)...I hope to become as a legend as Jan-Ove Waldner". Although Ma Long does not compare himself and Waldner directly, he shows full respect to Waldner and he may think himself can improve even further to reach the status of Waldner. I of course have faith in Ma Long. He is not playing for titles at this stage but for passion and joy and he is still making more history.
I hope Waldner can share his own thoughts on the same questions, who is the currently best (he correctly predicted that Ma Long would win 2015 and 2017 WTTC before the tournaments and Ma Long would beat Mattias Falck 4-1 before the final in 2019) and who is the best ever.