The issue is that they designed her in a very binary way.
To jungle and to hunt/dive. Her dam trailer depicts her as a hunter, not a god dam tank w bot.
However since she released as such a squishy and easy to kite champion, tank builds were forced down her throat.
Why are her clear speeds so good? Because without them she fails at doing the very thing she was designed to do.
Don't get me wrong I love me a bit of top lane ad rek sai. But her q scales so badly off ad as her primary damage source that it isn't worth it. She is just too squishy without beef and the E has such a good ratio that the dmg is just nuts at max fury.
^^^ there is damage/lack thereof in all the wrong places and an insane lack of beef
If they nerfed her E ratio, adjusted the scaling on q, and gave her some beef instead then she could build more damage without being a really crap dmg based diver.