I agree about not obsessing on just one aspect of your playing.
You should give yourself multiple challenges no matter what stage of playing your in. That being said you don't need to make unrealistic challenges for yourself. You just want variety.
An example of a short practice schedule would be:
5 minutes on A minor chord progression
5 minutes on E minor pentatonic scale
5 minutes on sweep picking arpeggios
10 minutes on improvisation(lead playing)
15 minutes on learning a song