Would I be correct in saying that the real issue with with Riot's balance team...

...is that too often they change too many things about a champion or role at once without showing any sort of caution.

Right now, people aren't necessarily annoyed by the fact that Ahri got nerfed, or that DFG got removed - they're annoyed by the fact that that both were done in a single patch.

What should Riot have done? They should have removed DFG and left Ahri untouched for Patch 5.2 and identified things such as what item Ahri players substituted DFG with, how much her overall power decreased (if at all), whether it altered the timing of her power spike, or if her play pattern changed.

I would have been up the the challenge. Is Lich Bane a suitable replacement? A different item to provide the missing CDR? Could I become slightly more CC-oriented and build a Rylai's? Or could I offset the missing damage by purchasing Seraph's embrace or some other high-AP value item?