"Janna is too effective overall"

As long as she is a easy to use, point and click shieldbot and now respectable point and click damage in lane with press skillbutton to deny hardengage and AoE heal she will remain a problem because she is disproportional more easy to use than she is to play against. Hence the real problem of Janna is inherent to soloQ. In soloQ you lack the team composition, coordination and player synergy to properly teamfight an enemy Janna. Any engage that is not perfectly executed by multiple players on different layers, baiting out her Q maybe shield, correct timing and sequencing of abilities and decision making will easily, just easily be completely denied by Janna. For how userfriendly Janna is you just can't achieve that required level of counterplay to her kit in soloQ.