QoL stuff for Janna
So, it's been pretty much since Season 4 changes dropped and still Janna's in an obnoxious spot. What she needs at this point isn't even buffs but QoL to make it so the power in her kit is actually delivered because right now squeezing benefits out of it is kind of difficult as hell.
The Passive: Gives, on average, 15 MS. Most of the time it's called "invisible power" because the benefit is literally impossible to spot. Because usually, the benefit isn't exactly helping you-Janna 's passive gets you back to lane roughly 2 seconds faster than normal from base (woooooow so op)
So what does it need? Friggin RANGE. half the time in lane you're not even granting it to your lane partner, and FORGET about making a jungler gank faster, guving it actual gameplay. 700 range would be, in my opinion, exactly enough to require a little positioning play from Janna while not hindering gameplay. Also a super slight visual effect on buffed allies would be nice too.
Next up: Dat E buff. It almost never happens. Why put a late game scaling on a skill you'll be using late game to protect people from incoming damage, if it doesn't continue after they take the damage you used the skill to mitigate? As it is you basically have to choose betwee getting damage mitigation or getting a buff while very few other skills work like that if they don't grant ENORMOUS (see Morgana black shield) addital utility like immunity from all cc.
Examples of similar skills that persist after damage is taken:
Ori Shield defense buff Lulu Shield pix attack buff Karma shield speed buff
With those benefits, Janna would actually have access to all the power in her budget (besides, of course, the healing from her ult usually, the MS from Zephy when she actually needs it ( fighting enemies), or the full damage or cc from her Q.