well, it is quite a long story.
First of all, let me say that I do not oppose anyone inventing and using his own phonetic spelling for Cantonese. I have done that myself. However, what is confusing and what is natural, depends on one's origin, on which other languages he learned, and simply on personal taste. Therefore, if anyone endeavors to publish some teaching material, as you are doing it with your website, it should be the best strategy to follow a common standard. In my experience, the most confusing thing of all is having to switch romanisation scheme when using another text book.
Unfortunately, there is no official standard for Cantonese like pinyin is for Mandarin. But Yale is used today in most text books, grammar books and dictionaries, so I'd call it a de facto standard. Jyutping (not yuetpin, I got confused with Lau romanisation) is new, better and seems to have the backing of some kind of semi-official organisation. But it has yet to make its way into the text books.
2. English spelling
Why are those systems so different from what you feel is phonetical ?
Why don't they use English spelling ?
Of course, all romanisation systems are phonetical. It is just a matter of definition, what a specific letter stands for. As each language has its own set of sounds, each language needs (!) and has its own definition. What you are essentially trying to do, is to use English spelling as the model for Cantonese romanisation. But you cannot hope to cover all Cantonese sounds in this way, as the sound systems of two different languages never completely overlap. Example: the Cantonese "yu" sound does not exist in English. Therefore, any beginner should make the extra effort to work on the sounds of the new language,and this necessarily implies learning a new spelling system. You are doing the same when learning French, German, Italian...
I believe, it is the best to search for the most simple, consistent and practical system. I am afraid to say, that English spelling is neither simple nor consistent. In fact, spelling is one of the hardest bits for those learning English as a foreign language. The history of Cantonese romanisation systems, from the one used by the colonial administration of Hongkong, to Sidney Lau (1970s), to Yale (in fashion in the 1990s, though invented much earlier), to Jyutping (1997), was driven by the desire to get rid of the inconsistencies of older systems, but in retrospective turns out to be a history of increasing emancipation from English spelling (i.e. in the opposite direction as you proposed).
Let me illustrate that:
Step 1: The early British colonial administration of Hongkong tried to use pure English spelling. Example: "Kowloon" which is "Gaulung" in Jyutpin. Cantonese distinguishes a 'g' and a 'k' sound, but they are more aspirated than in English. To English ears, it was all 'k', so you will not find any Chinese street or place name in Hongkong which starts officially with a 'g'. Lau romanisation solved this problem by writing 'g' even if an englishman still hears 'k' (and similar problems for 'b'/'p' and 'd'/'t').
Step 2: Yale improved Lau concerning the confusing English style use of the 'o' (see chart).
Step 3: Jyutping improves over Yale by e.g. stopping the inconsistent use of 'y' both as a consonant and as a vowel. Another improvement is the distinction of 'oe' and 'eo'. Yale still used 'eu' for both, leading to confusion even among some teachers, which claimed that the two were essentially the same sound with different lengths. Both sounds are not familiar to English ears, and I guess that is why the problem was spotted so late.
Hope this helped to provide some insight as you wished.
To sum it up. English spelling has been tried before, but it turned out that its use for Cantonese leads to problems. So it was abandoned in favor of a more latin use of the Roman alphabet. Well, fair enough.