(NOTE: THIS IS COMPLETELY FOR FUN. Obviously things would need fine tuning and some compensations would need to be added - this is almost all just buffs. I just thought of some things that might make Janna more interactive and less reactive. I'll include reasoning for fun.)
Passive - Divine Winds:
Effect radius: 850
Cooldown: 300 seconds
Once every 5 minutes, Janna can select a large zone centered anywhere on the map. Allies within that zone move gain 8% bonus movement speed, and enemies within that zone are slowed by 5%.
At level 18, Janna permanently gains a region of Divine Winds centered on herself, which disables this passive elsewhere on the map.
[Reasoning: Active passives are the new thing, and keeping with the Air Elemental concept and her lore of helping sailors, being able to aid select regions of the map seems right up Janna's alley. The speed adjustments would definitely need fine tuning. The level 18 zone allows Janna's passive to transition to late game team fights instead of focusing on laning assistance.]
Q - Howling Gale:
Target range: 825-1350 [reduced max range]
Collision radius: 60-80 [rewards charging with better zone control]
Cost: 90/105/120/135/150 mana
Cooldown: 14/13/12/11/10 seconds
Damage: 70/105/150/195/230 (+55% AP) magic damage (50% damage to minions and monsters) [allows actual dueling with other supports without pushing too much]
Active: Janna summons a whirlwind at her current location which charges up over 3 seconds. Its range and knockup duration increase for each second it charges. Its collision width gradually expands as it travels.
At the end of the duration, or upon reactivation, the whirlwind launches itself in the target direction, dealing magic damage to all enemies it passes through and knocking them up for 0.5-1.25 (based on seconds charged) seconds. If the whirlwind is allowed to fully charge, enemies knocked up by the ability are slowed by 60% for 1 second upon landing.
[Reasoning: Janna's Q sucks at max charge. There's no payoff to it other than range and a slightly longer knockup. I stripped the damage increase so I could increase the base damage to better help with duels without contributing to mass pushing, while rewarding charging it up with better zone control. To adjust for the increased hit box, I reduced the max range.]
W - Wild Zephyr:
Effect radius: 600
Cost: 65/80/95/110/125 mana
Cooldown: 15 seconds
Magic damage: 50/85/130/165/190 (+60% AP)
Bonus movement speed: 9/11/13/15/17% (+2% per 100 AP), decays over time
Slow: 18/22/26/30/34% (+4% per 100 AP), decays over time
Active: Janna's elemental ghosts Janna and all allied champions within range, granting them bonus movespeed for 3 seconds, while dealing magic damage and slowing all enemy champions within range.
[Reasoning: Janna's W is currently very binary, and punishes you for saving your allies. I went with a more proactive ability, similar to a mini Coin active or Sivir ult, which also contributes to escapes by slowing enemies. The damage is minimal, far less than her current single-target W, but enough to help contribute to skirmishes. Janna only gets the ghosting effect upon activation, but she also gives it to her allies. It is a high-risk ability with a short range when used in the heat of combat.]
E - Eye of the Storm:
Target range: 800
Cost: 70/85/100/115/130 mana
Cooldown: 14/13/12/11/10 seconds [longer early, same late]
Shield strength: 70/115/160/210/260 (+75% AP)
Bonus AD: 10/17.5/25/32.5/40 (+10% AP)
Active: Janna shields the target allied champion or herself for 5 seconds, granting them bonus attack damage until the shield expires. Allies shielded by this ability gain 10% movement speed on-hit, stacking up to 30%, until the shield expires.
Eye of the Storm can be used on turrets, causing Janna to be credited for any kills it earns while the shield holds.
[Reasoning: Her E is a powerful ability, but shields just aren't interesting. To me, "Eye of the Storm" infers some kind of chaotic winds, which simple AD just doesn't reflect. I added a chase ability for ADCs she shields, allowing for enhanced kiting or chasing, depending on the situation. The AD bonus could probably be reduced to compensate, although it does have a longer cooldown early on this way. I did reduce the early shield to compensate for the increased utility for those level 1 fights, while increasing the late game shield to actually hope it can take more than one hit in the late game.]
R - Reverent Cyclone:
Effect radius: 600
Cost: 100 mana
Cooldown: 150/135/120
Heal per half second: 50/75/100 (+25% AP) (Maximum healing: 300/450/600 (+150% AP))
Active: Janna knocks back all nearby enemies up to 700 units based on their proximity to her, stunning them for 0.5 seconds, and channels for 3 seconds, releasing soothing winds that heal nerby allies every half-second while channeling. Enemies that are knocked back by this ability once are immune to additional knock backs.
Janna may move during the channel of Reverent Cyclone, but activating abilities, attacking, or reactiving this ability will cancel the channel, restoring 10 seconds of the ability's cooldown for each full half second of the channel remaining. Janna is slowed by 50% during Reverent Cyclone's channel.
[Reasoning: Janna's ult is great for disrupting fights, but is odd to use in the heat of battle as a real support ultimate. By condensing the AoE and allowing her to move at a slower pace during the channel, Janna turns into a roaming zone of CC and healing, rewarding the full channel of her ability while still making her vulnerable to retaliation. Also, about the name, a Monsoon is usually attributed to a huge rainstorm. I just figured something less associated with rain would fit better.
TL;DR - I'm dumb and find rewriting champs to be fun. Just ignore me.
's E passive is disabled while it is on cooldown.