I more or less agree with your points #1-4.
On the topic of criticism, I feel thusly... if work is genuinely mediocre, and all a person hears is good-natured praise, there's not all that much motivation to work harder next time, and to expand and improve one's technique.
Now, some people may be fine with maintaining their work on a relatively low level. Others may come to find that a more advanced level of craftsmanship is both more rewarding and more personally satisfying.
But if a beginner never gets a a genuine and honest critique, he may never have the chance to find out what level he is ultimately capable of.
When I first started models of any kind, I had no real frame of reference for comparison, so of course I thought my crap was good. But when I started browsing import model magazines, and started seeing other people's work on the internet, I was obliged to accept the fact that I was, in fact, not that good at all. This realization prompted me to seek guidance from those with more experience, and eventually helped me to attain much better results in my own work.
That's how anyone improves in any field really... by having someone point out the areas where one needs improvement.
For all you kids still in school... think about your classroom environment. Don't your teachers correct you when you've made a mistake, or when you're not approaching something the right way? It's all meant to spur the student on to greater heights of achievement.
So if the modeler here would like to go on, and improve, he should be open to comments. If he's perfectly happy with his current level and has no wish to improve, then he's free to disregard all comments here. Pretty simple, no?