SuStel:

You tell me: what is the difference between "the axe fell" and "the axe has fallen"?

I can't think of any difference between them. The only thing I can
think of, is that the "the axe has fallen", perhaps sounds a little
more "vague". But that aside, I agree that there is no "detectable"
difference between them.

Exactly. The difference is purely grammatical. "The axe fell" is simple past tense; "the axe has fallen" is present perfect tense.

Klingon doesn't have simple past tense or present perfect tense, so there's little point in asking which is the better translation. Use whichever translation is most appropriate for what you're saying or writing. Sometimes either one will do.

-- 
SuStel
http://trimboli.name