Here are some of the major differences between the vowels of western Canadian English and the cardinal vowels whose symbols we have been using to right them.
We can see this in formant plots:
For many younger speakers, the high central rounded vowel symbol  would be more accurate. Some extreme versions, like exaggerated imitations of California dude, are almost as front as the front rounded [y] of French lune 'moon'.
You might have to deliberately pull your tongue body backwards in order to produce a cardinal [u]. The closest most Canadian English speakers will get in natural speech is when the [u] comes before a dark , as in school. Anticipating the velarization on the  helps keep the [u] in a back, velar position. You should be able to hear the difference between the almost cardinal [u] in school [sku] and the quite front [u] in cute [kjt].
(The backing effect of  is especially noticeable when it doesn't work. Many younger speakers can pronounce slang cool (or kewl) with the /u/ as far front as it would normally be for cute.)
Even in accents of Canadian English that use monophthongs for bait and boat, the monophthongs will typically be lower than cardinal [e] and [o].
This feature of British English is also found in many other dialects of English. Even in many dialects of North America, the beginning of the /o/ diphthong is becoming increasingly centralized and increasingly unrounded.
Nor do diphthongs always have to move upward and to the front or back. It is particularly common for languages to have "centring" diphthongs, where the off-glide is schwa rather than [j] or [w].
In English, some parts of the U.S. use  or [e] for /æ/, bad [bed]. Centring diphthongs are also used widely in "non-rhotic" dialects -- the loss of historical  from syllable codas does not necessarily result in homophones: