Even if not a classic no.9, I can't see a reason why he couldn't replace the current Suarez in that position.
He runs more, presses more, tracks back more, passes better, plays one-twos wonderfully and has a good shot.
Not a dribbler, but is suarez considered one nowadays? What we need is a pacy, dribble capable, penetrating left winger a.k.a someone like Fati or Dembele.
Although the first is 16 years old and the second.. he is what he is, until now at least.
P.S. Fati doesn't seem that fast to be honest, so Dembele is our only truly fast player.