Yes, a great idea. Most of my playing is song oriented. Finding the song key, and related mode/scale is important. Then I can attempt to solo over the chord progression.

I think that at the end of the day, scalar practice has to be song/riff oriented otherwise, why play the scale in the first place? Now of course, that's not to say that practicing your scales and arpeggios is a bad thing, but I personally try to not spend too much time working a scale in a strictly up/down manner; it's got to be some cool little sequence or a hunk of a chop that sounds cool that I'd like to assimilate....