As David has seen fit to post it, thinking they were indeed 'improvements', I'd like to just quickly post my 'reasonings why'....
I think seeing 'why' is sometimes useful in helping writers determine not only how they fit better here, but may apply to other situations as well.
Changes were done to the first two sentences.
As originally written,
“What is a gift unasked for and unwanted, a gift
that leaves its giver’s hands but not their heart, a gift
that is the heaviest burden any shall ever carry?” She rested her face against her pony’s shoulder and closed her eyes and stood there,
eyes closed.
"that leaves" of course uses my favorite object of dread, 'that'. It cites a state of motion, but in a somewhat static way.
The adverb form 'leaving' both eliminates 'that,' and uses a little more powerful, active form of motion, giving a slightly stronger impresson/picture of 'motion' to the reader.
Same with "that is". "That is" is a static statement of 'being". of 'exists as'. the gift 'exists as' the heaviest burden... again in a more active motion kind of way.
Thus, the suggestion of using "being" the heaviest burden, 'being' also eliminating 'that' and incorporating a slightly more 'active' motion perspective.
In addtion, when David changed it, HE himself picked the subtly better, smoother "and never wanted" rather than using 'and unwanted'.. simply flows better. Also more 'exclusive' and 'powerful, as it indicates not just a momentarily situational 'unwanted' but a 'never.'
Then, I suggested the semi-colons after 'wanted' and 'heart'. They are 'stronger' than commas, better than periods. There's nothing wrong with the commas OR the periods.. but the semi-colon provides a better 'separation' without being the 'total disconnect' a period sometimes intrudes.
Since it all refers to the same original 'gift', semi-colons are just a bit more powerful into the equation of the first sentence, (and the
riddle itself).
All in all, the power of that first sentence is, in my opinion, substantially increased. And he must think so too, as he adopted it...
Then the 'eyes closed' in the 2nd sentence was just because it 'duplicated' what was already said, not really 'adding' anything extra to the picture, and would be assumed by the reader.
Food for thought and application if/as/whenever it may fit your circumstances.
Again, always keep the receipt and impact on the reading audience in mind.
ADDED NOTE: (I may have mentioned it before)
... "and" and the comma are not always interchangeable.
'and' can be a very static conjunction, combining but leaving things laying a bit flat a bit, where a comma can add power.
Example: the baby was pouting and crying and raising a fuss constantly.
vs. ............ the baby was pouting, crying, raising a fuss constantly.
vs. ........... the baby was pouting; crying; raising a fuss constantly.
note the differences in flow and power of the 3 presentations of the same thing. the author's delight is in choosing which one fits not only the individual sentence, but the entire scene trying to be set. Sometimes you want the lesser. Sometimes the greater.
You are the artist; craftsman; painter working to bring the picture home. Make it
the one you really want to achieve.