I don't think an example sentence is necessary for either 'sprunghaft' or 'wing it,' and in any case I agree that the two sides of this translation don't seem to match, so I would support just deleting the sentence.
LEO already has four other entries for sprunghaft
as an adjective, namely: erratic, excursive, mercurial and volatile.
While we're at it I would suggest adding 'sprunghaft (adj.) = disjointed' as well, and if possible, also all the other senses above:
rapid, sharp, sudden, abrupt, by leaps and bounds.
Other ideas might be 'unfocused' or 'jumping from one topic/idea to another.' As usual, I feel that when there's no direct equivalent it never hurts to have a few more options.
I would also suggest marking 'excursive' as formal.
LEO also has two normal entries for to wing it [coll.]
. One is 'improvisieren, which seems right.
The other is 'voreilige Schlüsse ziehen,' which just seems wrong as far as I know. Unless anyone has evidence for that, I would recommend deleting it too.
It might be nice to add another option or two for 'wing it,' but I don't know anything else to suggest myself.