I liked Kaufmann's better, but that could just be due to the fact that he translated most of Nietzsche's work. I do commend you on your translation though.
Yes, he does use more 'normal' words I think. His words seem less 'forced' so to speak.
I think what he was trying to say with the poem is that a life in the public eye or a life in obscurity are not the healthy ways to live. Finding balance between the two is worldly wisdom that everyone should live by.
I have the idea that Kaufmann's translation led you astray in this case.
Perhaps I should translate the German sentence by sentence so I can show you what I did and why I think Kaufmann's translation is incorrect. After that I think we should get back to what Nietzsche ment by it.
Bleib nicht auf ebnem Feld!
Ebnen means level, same, known. The term 'beaten path' comes to mind. Literally Nietzsche is saying not to stay in the fields that you/everybody know(s).
Steig nicht zu hoch hinaus!
I would like to say that I had forgot the word 'nicht' (which means not, denial, reversal). I have added it now.
On this line Kaufmann and I agree. It is about not rising above what is around you; keeping sight of what takes place.
On this line Kaufmann and I agree as well. It states that the world is most beautifull, best seen. In the next sentence a clarification of when is given.
Kauffmann and I sort of agree here too. It is about medium, half. The word 'halber' means the half of something. To me the height of a youg child come to mind.
When it comes to meaning I think it is about Nietzsche's idea on how to live ones life. Try to look around (into other 'fields'), try to see what is around you (and not ponder about things more beautifull; aesthetical ideals). And this is embodied in how children live (the way the world is viewed from medium height); a 'real' living is known by children who are not lured into a comfortable life or into aesthetical fictions, but simply 'live'. This seems much more inline with Nietzsche's philosophies than the mediocre idea you are proposing (Which seems to 'flow' from Kaufmann's translation. I do not think it is what he ment though).
That is why I think it is the nicest of poems. He states his philosophy in a way which I have never seen him do in his best known works; there he rages and roars (so to speak
). It is as if he is showing the child within himself, or telling us to find our child inside ourselves to me. What do you think?