you raise some interesting points but your wrong..
1. you don't have to of made something in flash to know what a good flash is...all you have to of done is watched a few flash's and you can pick up on what is good and what isn't. same thing goes for knowing what is wrong with a flash eg: if the sound in a flash is so crackly you can't understand the charecters at all
however...to fully understand and respect how much work goes into a flash you definatly have to of made a one.
2. if somebody says in a review "this was not very good try harder" isn't that just a different way of saying "i didn't like this movie at all...work on the story, sound, animation, graphics ect or make something else"
people can't be telling artists how to do everything in flash...reviews aren't for learning flash...that's what tuturials are for...newgrounds even has a link to the good tuturials on the portal front page.
3. i am aware i am not saying anything about the flash (breaking reviewing rule #2) but hopfully this will help you understand some things about reviews...