The increased base damage on Evelynn's whiplash just doesn't resolve the problems with farming, clearing, or damaging the enemies she's supposed to damage.
I would suggest moving the base damage increase to hate spike's initial dart/spike, and giving it (the dart/spike only) a 0.2 AP scaling increase. Or increasing hate spike's overall base damage, and a small increase to whiplash's scaling. Or perhaps giving Hate spike the same cooldown reduction as vs monsters if the initial spike procs her charm/hits a charmed champion.
Hate spike is the bread and butter of her early clearing, but it's not strong enough to clear at a decent speed as the match continues, since the nerfs to whiplash has taken out a massive chunk to her ability to farm the jungle in the mid-late, which should be the easiest time for her to farm.
Against champions, Evelynn's main problem is that her best sources of damage are too delayed to be significant when on equal grounds mid-late, and she is heavily outbursted by most assassins, many mages, and a good number of marksmen.