The Great Vowel Shift made English a better language because it added a unique flavor to it. While it brought some strange differences to the language, it did make it stand out from other English versions of the language. It can be considered one of the aspects that make the English language unique.
The Great Vowel Shift caused English words to adopt vowel pronunciations which are much more succinct. A vowel sound now is much more definitive. Prior to the Shift the English language may have been more lyrical but it was much less efficient. The Shift made specific words more understandable. Prior to this Shift a vowel sound might confuse a listener because the parameters of the specific sound were less definitive.
There can be no question that the Great Vowel Shift ranks among the greatest discoveries in human hostory. In fact, it is such am important transition in American history that we can see the plain results in the stellar product coming out of our government schools. Our little kidlets speak so well and have a terrific command of the english language - all thanks to the Great Vowel Shift.
When we talk about the GVS, we usually talk about it happening in eight steps. It is very important to remember, however, that each step did not happen overnight. At any given time, people of different ages and from different regions would have different pronunciations of the same word. Older, more conservative speakers would retain one pronunciation while younger, more advanced speakers were moving to a new one; some people would be able to pronounce the same word two or more different ways. The same thing happens today, of course: I can pronounce the word "route" to rhyme with "boot" or with "out" and may switch from one pronunciation to another in the midst of a conversation.