Creativity and a willingness to "break the door down", so to speak. He just does not stop attacking the defense. There were goals he created during his loan season simply because he wore the opposition down over the course of the match. Lennon is the more tireless worker across the entire pitch, but in the final third his tenacity doesn't match Deulofeu's.
....perhaps it shouldn't be Deulofeu v Lennon but I describe it as perspiration v innovation. I'm not criticising Lennon but Deulofeu gives us something different.