A very interesting question! I'm not sure I can answer it as fully as it deserves, but since it's been seven hours without any replies I'll give it a try.

Classically the Chinese gentleman is supposed to be the master of the Four Arts (四艺): Playing the Guqin (琴), playing chess (棋: to be specific, Go, which was invented in China and mastered in Japan, like so many things, but never mind), calligraphy (书), and painting (画). Besides that he is almost certainly expected to hold a degree from the imperial examinations: the higher, of course, the better. Juren is, I think, the lowest rank considered socially acceptable to be a gentleman. Finally, he must absolutely on no account engage in mercantile activity or work with his hands. If you already know this, and are just looking for Republican and Communist perception of gentleman qualifications - sorry!

When the Empire was overthrown and the Republic was born, traditional ways of thinking did not change drastically with the older generation, though the younger generation became increasingly modern. There was a widespread reaction amongst the young against classical emphasis on the literary arts, and in favour of modern education in the sciences and the military.

The gentleman began to be transformed into a new and modern class: the intellectual. He is still expected be educated (now basically it means a university education, either in the US, the UK or Peking Uni/Tsinghua) and earn his daily bread by his brain and not by his hands. However, finance and the sciences became increasingly acceptable occupations for intellectuals. The main desire was for everyone, intellectuals included, to be useful in the construction of a newer, stronger, freer China. Traditional Confucianist gentlemen are held up as objects of scorn: they are thought to be hypocritical, always emphasising the importance of virtue while becoming a bloated and corrupt rentier class; they are thought to be uselessly literary, unable and unwilling to address the practical, technological challenges China faces from the dominant West; worst of all, they are thought to be failures, as the political and social system they espoused led China to lose a series of humiliating wars and a string of port-concessions to foreign powers. That is why Confucian gentlemen went on the decline, while the modern intellectual - scientists, engineers, doctors - rose in status.

Nevertheless, literary intellectuals are still revered in the Republic. Lu Xun, Xu Zhimo Hu Shih... China's reverence for men of letters, although now they are modern men of modern letters, continued to hold.

During the Great Proletarian Cultural Revolution, as you may guess from the name, intellectuals were denigrated and held up as objects of scorn. The best thing is supposed to be working with one's hands and earning one's bread by the sweat of one's brow. The literati, the intellectuals, even in some suicidal cases the expert scientist, are lumped together as good-for-nothings and packaged off for re-education through labour. The clearest expression of this depressing ideology can be seen from the movie Breaking with Old Ideas. Academic education, the foundation of the gentleman-intellectual, is considered uselessly theoretical. Manual labour and practical application are the only worthwhile things. It is selfish and greedy and reactionary to want a white-collar job with a good salary. Every child should aspire to be an industrial labourer or a peasant.

That madness lasted as long as Mao's death; after he died the pendulum swung back in the opposite direction. In modern China the classical Chinese gentleman is considered somewhat archaic by the vast majority of the populace. Now, the ideal man for ladies is supposed to be Tall, Wealthy and Handsome (高富帅); just where said wealth is obtained is, unlike in the past, not that much of a concern. Still, as the academic performance of Chinese in the Sinosphere as well as diaspora worldwide shows, academic achievement is back to becoming for most Chinese people the surest route to social respectability, as well as a good and safe standard of living.