Frans Helmerson talks about the work as a whole - it is necessary to identify folk elements from every movement (rhythms, articulations, accents, etc.): sophistication without losing its popular character.
The vibrato is too intense for the sound of this piece (the required character is more tender). Indications about agogics: keep the same pulse and do not take breaks that do not exist. Bow technique: both hands must change their character at the same time, with a deeper bow (more contact) and projection in last notes. Specific corrections on fingerings.
In a movement such as this, an expressive person like the student must distance himself to avoid being too carried along (expressiveness is there by itself).
Digression about the work in general: it is like a Brothers Grimm's tale (it experiences mood swings, going from the nicest fairy tale to the cruelest nightmare).