I believe I have found the perfect Romanization system for Taiwan. I call it "That-Horse-Isn't-Dead-Yet [THIDY] Pinyin" (in honor of the incessant flogging of the Tongyong versus Hanyu debate). THIDY Pinyin accurately reflects real usage patterns in Taiwan, because it doesn't exist, and so does not have to be taught in local schools.
Supporters of Tongyong Pinyin often argue that it is superior to Hanyu Pinyin because it's "easier to read" for foreigners, and because of its "versatility" for the different languages of Taiwan. As a foreigner, I do not see Tongyong as a better Romanization system for Chinese, rather it is only a nuisance. From cojones to cappuccino to Schadenfreude to chutzpah, we foreigners already have beaucoup foreign spelling systems to keep track of. Please don't burden us with another, not when there's already a world-recognized standard for that particular language.
Yes, we are confused at first by the "x" and "q" in Hanyu Pinyin, but no more so than by weird pronunciations in other languages, such as those listed above. And a quick glance at a phrase book is enough for most people to adapt.
And there is nothing particularly "versatile" about Tongyong either. This is a red herring, no more meaningful than to say the Latin alphabet is versatile because it can be used to transcribe most European and American languages -- even Chinese and Taiwanese, with a bit of tweaking.
The designers of Hanyu were forced to make some compromises (such as "x" and "q") in order to shoehorn Chinese pronunciation into the English alphabet. But the choices they made resulted in an elegant, almost irreducibly simple system, which respects the linguistic traditions of both the Chinese language and the Latin alphabet.
For example, although the Hanyu reading of "q" is completely novel to an English speaker, it is easy to absorb, because we are used to consonants having both "hard" and "soft" (velar and dental) pronunciations, such as "g" and "c" in English. The Hanyu "q" fits well into this mental slot.
The Hanyu "x" reflects the unique flavor of this phoneme, which as far back as Wade-Giles ("hs") and Zhuyinfuhao ("ㄒ") has been deemed distinct enough from "s" ("ㄙ") to warrant a separate way of writing. Furthermore, the variation in pronunciation of "x" among Western languages fairly approximates the linguistic drift in the pronunciation of some Chinese characters, such as "xing/hang" (行).
Changing these two consonants to "s" and "c" only adds confusion, by giving these two letters multiple readings in Tongyong. In Hanyu, every consonant has only one pronunciation. Only the vowels "a", "i", and "u" have multiple readings, one "high" and one "low" for each. (Linguists describe vowels by the position of the tongue in relation to the soft palate, on a low-to-high scale: "oo, oh, ah, eh, ih, ee, ng.")
The Hanyu letters "j," "q" and "x" naturally distinguish these vowel readings, because in order to sound them properly, the tongue must be in a high position. Whereas the Hanyu "s" is produced with the "tip" of the tongue (about the first 1cm), the "j," "q" and "x" are made with the "blade" of the tongue (the next 2cm or so). With the tongue in this position, it's nearly impossible to produce a "low" vowel sound.
There are many such levels of interlocking consistency in Hanyu Pinyin, which aid in the learning of Chinese pronunciation. Many of these are broken or twisted in the Tongyong system.