Yeah, Korea should also have stayed with Japan, things were awesome under them.
Allow me to explain this, please. (For the moment, disregard where i am from...
)
Japanese rule in Taiwan was markedly differently from its rule in Korea, or other parts of its occupation.
As Japan's first overseas colony, a showpiece to demo westerners its capability to own a colony, Taiwan received huge improvement from Japan, in economy, industry, public work, education and even culture.
Japanese blended in to locals, many intermarried to Taiwanese, one famous anthropologist married aboriginal wife and adopted two, to learn their language.
Unequal treatment had gradually meltdown, before the end of pacific war, Japanese government had consider to abolish 63 law, colonial law, to give Taiwanese an equal status under Japanese constitution, and upgrade Taiwan to a official prefecture.
The close interaction between Japanese people and Taiwanese is far beyond outsiders imagination. (Especially Chinese)
To Taiwanese, though not the same ethnic group, Japanese are more advance, more reasonable to deal with. That's one of the reason why most of the uprising ceased before 1915. (Another reason is basically Taiwanese didn't have the idea that "Taiwan is an independent country lost to Japan", rather just a change of the ruler, this time "not our kind", quite different from Korea's situation.)
Some scholars criticize the adaptability as slavery character of Taiwanese. After enjoying 4 times more of electrical power consumption than all mainland China sum up a year, telephony, cars...Naturally Taiwanese were more willing to identify themselves as Japanese than Chinese. Especially most Taiwanese, received mandatory education, up to high school, some to college, now can communicated fluently in Japanese.
If you disdain those war crimes IJA had committed, i truly agree with you. However, it's also true Japan did a great job in Taiwan, and even today welcomed by many.
No people is total evil...
Ironically, after the end of pacific war, the former enemy, KMT troopers came to Taiwan with the assistance from US, saw streets filled with Japanese signs, people speak Japanese, along with many advance facilities they had never seen in China, felt rather undignified and reminded what Japanese did to their homeland.
Theft, rape, robbery, disease, were rampant, brought by Chinese. Taiwanese stunted, jaw-dropping how can this country defeat Japan, contempt and doubt secretly grew in mind.
Finally the tension between the two different culture groups, unaware to US, erupted into 228 incident, KMT troopers with the help of US-made weapon, killed more than 18,000 of Taiwanese, later arrested and murdered more social elites to avoid similar uprising.
1949, after losing the civil war, KMT moved to Taiwan, one-minded on retaking the mainland China and securing their rule in Taiwan, paid few attention to infrastructure. Police, post office, farming...too many simply received those left by Japanese.
Without those infrastructure left by Japanese, KMT won't hold long against CCP attack. You can tell from the quick destiny of one KMT troop retreated to HaiNan.
Don't think Chinese won't commit the same war crime like Japanese. They just lacked the capability at that time. Historically, China can be as brutal as like burying 400,000 soldiers over one night (Battle of ChangPing) or just look at Tibet...
IMHO, Taiwan can act as an independent bridge (or strategic buffer zone) to China and Japan, the two powers in Asia, to promote unity and peace. Like Belgium in Europe.
For people who is interested in Taiwan's past, the book, Formosa Betrayed, by George Kerr, will tell you why Taiwan would rather stay with Japan.
http://www.romanization.com/books/formosabetrayed/index.html