Ashe > Jhin?

There seems to be no reason to pick Jhin over Ashe. Ashe just seems to be better in every way.

Ashe has a way better and more dominant laning phase. She doesn't need to reload, has greater attack range, has better harass with her W... and at level 6 she power spikes harder (her Arrow is a major pro-active threat that can start fights while also following up on Ganks... meanwhile, Jhin's is far less flexible and dangerous).

Ashe pushes towers harder.

At 2-3 items, Ashe performs way better against Tanks. They both do about the same damage on squishes unless you carefully time 4th shots.

If you're team is behind or you are behind... most of the time Ashe feels more useful and has greater come back potential.

If you're team is ahead... you still want Ashe. More DPS, vision, and has the arrow. Jhin's W sounds good on paper but its hard to aim and he brings much less damage. Meanwhile, Ashe feels like she actually has more CC with her perma slows.

The biggest issue though is that they are both immobile... but Ashe just feels more dominant and with more damage at all points of the game.