I don't like the use of As in this sentence. To me it's wrong.
I suggest:
For a teacher, there's nothing more satisfying than seeing students progressing.
Though it's common, it is best avoided in writing assignments.
Why do you think so? What kind of writing assignments are you thinking of?
Please remember to state that you are not a teacher.
If a student does not want to lose points for a dangling modifier, he or she should avoid it.
You could consult writing handbooks to know why. Would you tell an SAT taker to use a dangling modifier? Probably not.
As a teacher, nothing can compare with seeing the progress of students.
The "as a teacher" in the original is a kind of dangling modifier. Though it's common, it is best avoided in writing assignments.
"Tell my mother that her other sons shall comfort her old age,
And I was, aye, a truant bird, that thought his home a cage;
For my father was a solder, and, even as a child,
My heart leaped forth to hear him tell of struggles fierce and wild [. . .]."
-- Caroline Elizabeth Sarah Norton, "Bingen on the Rhine"
You know, I really don't think I would describe even as a child as 'dangling' here because the referent is obvious.
I agree with the dangling-modifier verdict. It may be worth noting that the sentence could be fixed by placing the "as"-phrase at the end.
Nothing can compare with seeing the progress of students as a teacher.
In that sentence, the "as"-phrase doesn't modify a noun. Rather, it functions as an adverbial within the gerund phrase headed by "seeing."
Unfortunately, I don't think it's grammatically possible to analyze the original as containing a fronted "as"-phrase related to that sentence.
Can I put a comma before "as a teacher"?
Great example above, Phaedrus.
You know, I really don't think I would describe even as a child as 'dangling' here because the referent is obvious. Would you agree that 'dangling' applies only when the referent is unclear?
I think that pedantry doesn't really work in these cases, because we tend to assume the most logical interpretation, and that is not that the person was wrapped in red and gold gift paper. If we think what the person meant, we will generally get the right answer.
The thing is, the most logical interpretation in those cases would not lead a test-taker (in East Asia or the US) to gain points.
I don't think it would be a big deal for any examiners I know in the UK, and I'd be surprised if this was much different in the US. I suppose it does depend on what the test is testing exactly, but the point of school tests and exams in English designed for native speakers is to focus on critical thinking, reacting to and understanding texts, and expressing your ideas about things well. Students would not get penalised on some trivial technicality unless it caused a serious impediment to comprehension.
I understand that something like 'dangling' modifiers may be an issue in some parts of Asia, though, where there is often a very different idea of what language counts as 'correct' and what doesn't. Obviously, the test-takers there are almost exclusively non-native speakers, too.