As a traditional support champion, Janna already scales minimally in utility with AP in comparison to Lulu or Nami. In Lemonnation's words, outside of Monsoon and E, AP doesn't do much for her since the rest of her scalings are so selfish.
I am extremely confused and frustrated as to why you're punishing players for building AP on her while buffing her base effectiveness through an unnecesary Q buff. If I make the decision to build AP I'm doing so on the cost of the many other more traditional options because I want to increase the effectiveness of E and R, mainly. Why should we be doubly punished for it? It's not like it's common to achieve important amounts on AP on her, but when you do it's beause you made the sacrifice to access those inaccesible stats.
It stands to reason if you want to (for what motive, I don't know) buff Q's range, you should seek compensation in damage, which is largely superfluous on her. Why does Janna need a .65 AP ratio on q damage? But most importantly, why are Janna players being punished for building AP when it's already a very specialized build that requires a 3 second channel to see maximum benefits?
It doesn't even ring like a balance change, it's not like the challenger or professional builds for Janna include any AP, it just seems like an arbitrary decision to punish a secondary build to make room for an inexplicable buff.